diff --git a/xml/System.Diagnostics.Tracing/DiagnosticCounter.xml b/xml/System.Diagnostics.Tracing/DiagnosticCounter.xml
index 5e38b479998..c8f6b15b6f1 100644
--- a/xml/System.Diagnostics.Tracing/DiagnosticCounter.xml
+++ b/xml/System.Diagnostics.Tracing/DiagnosticCounter.xml
@@ -65,9 +65,18 @@
         <ReturnType>System.String</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets or sets display name of the counter.</summary>
+        <value>The display name of the counter.</value>
+        <remarks>
+      <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+The `DisplayName` provides a more display friendly name for the consumer side of the metrics. For example, a counter named "gen-0-gc-count" is better displayed as "Gen 0 GC Count". To do so, `DisplayName` can be used to be reported as part of the payload.
+
+   ]]></format>
+
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="DisplayUnits">
@@ -137,8 +146,8 @@ After being disposed, this counter will do nothing, and its resources will be re
         <ReturnType>System.Diagnostics.Tracing.EventSource</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the EventSource that this counter is attached to.</summary>
+        <value>The EventSource that this counter is attached to.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -158,8 +167,8 @@ After being disposed, this counter will do nothing, and its resources will be re
         <ReturnType>System.String</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the name of this counter.</summary>
+        <value>The name of this counter.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Diagnostics.Tracing/EventCounter.xml b/xml/System.Diagnostics.Tracing/EventCounter.xml
index 0fbc9ec7bff..5d7812bb30b 100644
--- a/xml/System.Diagnostics.Tracing/EventCounter.xml
+++ b/xml/System.Diagnostics.Tracing/EventCounter.xml
@@ -34,10 +34,11 @@
   <Docs>
     <summary>Provides the ability to collect statistics for very frequent events through the  <see cref="T:System.Diagnostics.Tracing.EventSource" /> class.</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[  
-## Remarks  
+      <format type="text/markdown"><![CDATA[
 
-For an example of how to use the <xref:System.Diagnostics.Tracing.EventCounter> class, see the [Introduction Tutorial: How to measure performance for very frequent events using EventCounters](https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.Tracing/documentation/EventCounterTutorial.md) topic.
+## Remarks
+
+For an example of how to use the <xref:System.Diagnostics.Tracing.EventCounter> class, see [Introduction Tutorial: How to measure performance for very frequent events using EventCounters](https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.Tracing/documentation/EventCounterTutorial.md).
 
    ]]></format>
     </remarks>
@@ -158,9 +159,16 @@ For an example of how to use the <xref:System.Diagnostics.Tracing.EventCounter>
         <Parameter Name="value" Type="System.Double" Index="0" FrameworkAlternate="netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="value">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="value">The value to be written.</param>
+        <summary>Writes the metric if performance counters are on.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+    ## Remarks  
+
+    For an example of how to use the <xref:System.Diagnostics.Tracing.EventCounter.WriteMetric(System.Single)> method, see [Introduction Tutorial: How to measure performance for very frequent events using EventCounters](https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.Tracing/documentation/EventCounterTutorial.md).
+
+       ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="WriteMetric">
diff --git a/xml/System.Diagnostics.Tracing/IncrementingEventCounter.xml b/xml/System.Diagnostics.Tracing/IncrementingEventCounter.xml
index 9d9e13a6645..3b46a8289a3 100644
--- a/xml/System.Diagnostics.Tracing/IncrementingEventCounter.xml
+++ b/xml/System.Diagnostics.Tracing/IncrementingEventCounter.xml
@@ -18,7 +18,11 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
 
-`IncrementingEventCounter` does not calculate statistics like mean or standard deviation because it only accumulates the counter value.
+## Remarks
+
+`IncrementingEventCounter` is used for keeping track of values that are always increasing, such as the total number of requests, the total number of exceptions thrown, etc. For such metrics, simply reporting the total value is not necessarily useful for monitoring its health. For example, keeping track of how many bytes have been allocated in total for the entire duration of the process is not useful for diagnosing any potential issues from allocating too much memory. A metric that would help us is how many bytes were allocated in the past minute, hour, or some arbitrary time interval, and not the entire duration of the process. `IncrementingEventCounter` can be used to keep track of and report just the increments over a time interval that was specified by the consumer of the metric.
+
+`IncrementingEventCounter` does not calculate statistics like mean or standard deviation because it only keeps track of the increments over a period of time.
 
     ]]></format>
     </remarks>
@@ -46,7 +50,9 @@
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
-Incrementing event counters live as long as the <see cref="T:System.Diagnostics.Tracing.EventSource" /> that they are attached to unless they are explicitly disposed.
+## Remarks
+
+<xref:System.Diagnostics.Tracing.IncrementingEventCounter> live as long as the <xref:System.Diagnostics.Tracing.EventSource> that they are attached to unless they are explicitly disposed.
 
          ]]></format>
         </remarks>
@@ -68,9 +74,17 @@ Incrementing event counters live as long as the <see cref="T:System.Diagnostics.
         <ReturnType>System.TimeSpan</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets or sets the rate at which this metric should be displayed as.</summary>
+        <value>Gets or sets the rate at which this metric should be displayed</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+
+## Remarks
+
+The value of the `DisplayRateTimeScale` property is included as a string in the payload.
+
+         ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="Increment">
diff --git a/xml/System.Diagnostics.Tracing/IncrementingPollingCounter.xml b/xml/System.Diagnostics.Tracing/IncrementingPollingCounter.xml
index 9785b6525c7..e955a3cec9b 100644
--- a/xml/System.Diagnostics.Tracing/IncrementingPollingCounter.xml
+++ b/xml/System.Diagnostics.Tracing/IncrementingPollingCounter.xml
@@ -17,8 +17,16 @@
     <summary>Provides a variant of <see cref="T:System.Diagnostics.Tracing.EventCounter" /> for variables that are ever-increasing, such as the number of exceptions in the runtime.</summary>
     <remarks>
       <format type="text/markdown"><![CDATA[  
-   
-`IncrementingPollingCounter` does not calculate statistics like mean and standard deviation because it only accumulates the counter value. Unlike <see cref="T:System.Diagnostics.Tracing.IncrementingEventCounter" />, this takes in a polling callback that it can call to update  its own metric periodically.
+
+## Remarks
+
+<xref:System.Diagnostics.Tracing.IncrementingPollingCounter> objects live as long as the <xref:System.Diagnostics.Tracing.EventSource> that they are attached to unless they are explicitly disposed.
+
+`totalValueProvider` is a method used for polling the values at the interval specified by the listener. This method is expected to return an incrementing float value; otherwise, an increment of a negative value may be reported.
+
+`IncrementingPollingCounter` does not calculate statistics like mean and standard deviation because it only accumulates the counter value. Unlike <xref:System.Diagnostics.Tracing.IncrementingEventCounter>, this takes in a polling callback that it can call to update  its own metric periodically.
+
+For an example that uses <xref:System.Diagnostics.Tracing.IncrementingPollingCounter> inside the runtime as for runtime performance counters, see the CoreCLR source for [RuntimeEventSource](https://github.com/dotnet/coreclr/blob/master/src/System.Private.CoreLib/src/System/Diagnostics/Eventing/RuntimeEventSource.cs) on GitHub.
 
     ]]></format>
     </remarks>
@@ -42,16 +50,10 @@
       </Parameters>
       <Docs>
         <param name="name">The name for this <see cref="T:System.Diagnostics.Tracing.IncrementingPollingCounter" /> instance.</param>
-        <param name="eventSource">The event source.</param>
-        <param name="totalValueProvider">To be added.</param>
+        <param name="eventSource">The event source this instance is a part of.</param>
+        <param name="totalValueProvider">A method that will be used to poll the value.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Diagnostics.Tracing.IncrementingPollingCounter" /> class.</summary>
-        <remarks>
-          <format type="text/markdown"><![CDATA[  
-
- <xref:System.Diagnostics.Tracing.IncrementingPollingCounter> objects live as long as the <xref:System.Diagnostics.Tracing.EventSource> that they are attached to unless they are explicitly disposed.
-
-        ]]></format>
-        </remarks>
+        <remarks>To be added.</remarks>
       </Docs>
     </Member>
     <Member MemberName="DisplayRateTimeScale">
@@ -70,9 +72,16 @@
         <ReturnType>System.TimeSpan</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets or sets rate at which this metric should be displayed as.</summary>
+        <value>The rate at which this metric should be displayed.</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+## Remarks
+
+The value of the `DisplayRateTimeScale` property is included as a string in the payload.
+
+         ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="ToString">
diff --git a/xml/System.Diagnostics.Tracing/PollingCounter.xml b/xml/System.Diagnostics.Tracing/PollingCounter.xml
index e4ee8149d97..457261323d8 100644
--- a/xml/System.Diagnostics.Tracing/PollingCounter.xml
+++ b/xml/System.Diagnostics.Tracing/PollingCounter.xml
@@ -18,7 +18,15 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
 
-`PollingCounter` differs from <see cref="T:System.Diagnostics.Tracing.EventCounter" /> in that it takes a callback function to collect metrics on its own rather than requiring the user to call <see cref="M:System.Diagnostics.Tracing.EventCounter.WriteMetric(System.Double)" /> every time.
+## Remarks
+
+<xref:System.Diagnostics.Tracing.PollingCounter> is a variant of <xref:System.Diagnostics.Tracing.EventCounter> that uses a callback method to poll for values rather than requiring the writer to explicitly call <xref:System.Diagnostics.Tracing.EventCounter.WriteMetric%2A?displayProperty=nameWithType> each time a value is tracked, `metricProvider` is a callback method that polls for values. The <xref:System.Diagnostics.Tracing.PollingCounter> instance polls and reports a value retrieved by calling `metricProvider` exactly once per the interval requested by the listener. 
+
+A <xref:System.Diagnostics.Tracing.PollingCounter> lives as long as the <xref:System.Diagnostics.Tracing.EventSource> that it is attached to unless it is explicitly disposed.
+
+`PollingCounter` differs from <xref:System.Diagnostics.Tracing.EventCounter> in that it takes a callback function to collect metrics on its own rather than requiring the user to call <xref:System.Diagnostics.Tracing.EventCounter.WriteMetric%2A> every time.
+
+For an example that uses <xref:System.Diagnostics.Tracing.PollingCounter> inside the runtime for runtime performance counters, see the CoreCLR source for [RuntimeEventSource](https://github.com/dotnet/coreclr/blob/master/src/System.Private.CoreLib/src/System/Diagnostics/Eventing/RuntimeEventSource.cs) on GitHub.
 
       ]]></format>
     </remarks>
@@ -43,15 +51,9 @@
       <Docs>
         <param name="name">The name for this <see cref="T:System.Diagnostics.Tracing.PollingCounter" /> instance.</param>
         <param name="eventSource">The event source.</param>
-        <param name="metricProvider">To be added.</param>
+        <param name="metricProvider">A method that will be used to poll the value.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Diagnostics.Tracing.PollingCounter" /> class.</summary>
-        <remarks>
-          <format type="text/markdown"><![CDATA[  
-
-Polling counters live as long as the <see cref="T:System.Diagnostics.Tracing.EventSource" /> that they are attached to unless they are explicitly disposed.
-
-        ]]></format>
-        </remarks>
+        <remarks>To be added.</remarks>
       </Docs>
     </Member>
     <Member MemberName="ToString">
@@ -77,4 +79,4 @@ Polling counters live as long as the <see cref="T:System.Diagnostics.Tracing.Eve
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>
diff --git a/xml/System.Diagnostics/Activity.xml b/xml/System.Diagnostics/Activity.xml
index a44743939e2..75af97709cd 100644
--- a/xml/System.Diagnostics/Activity.xml
+++ b/xml/System.Diagnostics/Activity.xml
@@ -19,16 +19,18 @@
   <Docs>
     <summary>Represents an operation with context to be used for logging.</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[  
+      <format type="text/markdown"><![CDATA[
+
+## Remarks
 
 An `Activity` has an operation name, an ID, a start time and duration, tags, and baggage.
-             
+
 The current activity can be accessed with the static <xref:System.Diagnostics.Activity.Current?displayProperty=nameWithType> property.
 
 Activities should be created by calling the constructor, configured as necessary, and then started with the <xref:System.Diagnostics.Activity.Start%2A> method, which maintains parent-child relationships for the activities and sets <xref:System.Diagnostics.Activity.Current?displayProperty=nameWithType>.
-            
+
 When an activity is finished, it should be stopped with the <xref:System.Diagnostics.Activity.Stop?displayProperty=nameWithType> method.
-            
+
 No `Activity` methods allow exceptions to escape as a response to bad inputs. They are thrown and caught (which allows debuggers and monitors to see the error), but the exception is suppressed, and the operation does something reasonable (typically it does nothing).
 
          ]]></format>
@@ -114,8 +116,7 @@ Note that <xref:System.Diagnostics.Activity> has a "builder" pattern: you call t
         <param name="key">The baggage key.</param>
         <param name="value">The baggage value.</param>
         <summary>Updates the <see cref="T:System.Diagnostics.Activity" /> to have a new baggage item with the specified key and value.</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
@@ -155,8 +156,7 @@ This key/value pair is included in the collection returned by the <see cref="P:S
         <param name="key">The tag key.</param>
         <param name="value">The tag value.</param>
         <summary>Updates the <see cref="T:System.Diagnostics.Activity" /> to have a new tag with the provided <paramref name="key" /> and <paramref name="value" />. .</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[
 
@@ -581,8 +581,7 @@ The root ID is a substring from the <xref:System.Diagnostics.Activity.Id> or the
       <Docs>
         <param name="endTimeUtc">The UTC stop time.</param>
         <summary>Updates the <see cref="T:System.Diagnostics.Activity" /> to set its <see cref="P:System.Diagnostics.Activity.Duration" /> as the difference between <see cref="P:System.Diagnostics.Activity.StartTimeUtc" /> and the specified stop time.</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -635,8 +634,7 @@ The root ID is a substring from the <xref:System.Diagnostics.Activity.Id> or the
       <Docs>
         <param name="parentId">The ID of the parent operation.</param>
         <summary>Updates this <see cref="T:System.Diagnostics.Activity" /> to indicate that the <see cref="T:System.Diagnostics.Activity" /> with an ID of <paramref name="parentId" /> caused this <see cref="T:System.Diagnostics.Activity" />.</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
@@ -667,12 +665,20 @@ This property should only be used in 'boundary' scenarios where an <see cref="T:
         <Parameter Name="activityTraceFlags" Type="System.Diagnostics.ActivityTraceFlags" Index="2" FrameworkAlternate="netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="traceId">To be added.</param>
-        <param name="spanId">To be added.</param>
+        <param name="traceId">The parent activity's TraceId.</param>
+        <param name="spanId">The parent activity's SpanId.</param>
         <param name="activityTraceFlags">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <summary>Sets the parent ID using the W3C convention of a TraceId and a SpanId.</summary>
+        <returns><see langword="this" /> for convenient chaining.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+
+## Remarks
+
+This method has the advantage that no string manipulation is needed to set the ID.
+
+        ]]></format>
+        </remarks> 
       </Docs>
     </Member>
     <Member MemberName="SetStartTime">
@@ -699,8 +705,7 @@ This property should only be used in 'boundary' scenarios where an <see cref="T:
       <Docs>
         <param name="startTimeUtc">The <see cref="T:System.Diagnostics.Activity" /> start time in UTC.</param>
         <summary>Sets the start time of this <see cref="T:System.Diagnostics.Activity" />.</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -746,8 +751,7 @@ This property should only be used in 'boundary' scenarios where an <see cref="T:
       <Parameters />
       <Docs>
         <summary>Starts the activity.</summary>
-        <returns>
-          <see langword="this" /> for convenient chaining.</returns>
+        <returns><see langword="this" /> for convenient chaining.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
@@ -910,4 +914,4 @@ Logically `TraceStateString` is just a kind of baggage (if flows just like bagga
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>
diff --git a/xml/System.Diagnostics/ActivitySpanId.xml b/xml/System.Diagnostics/ActivitySpanId.xml
index 24dd4f28da8..46373f355c7 100644
--- a/xml/System.Diagnostics/ActivitySpanId.xml
+++ b/xml/System.Diagnostics/ActivitySpanId.xml
@@ -189,9 +189,9 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="spanId" Type="System.Diagnostics.ActivitySpanId" />
       </Parameters>
       <Docs>
-        <param name="spanId">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="spanId">The instance to compare.</param>
+        <summary>Determines whether this instance and the specified <see cref="T:System.Diagnostics.ActivitySpanId" /> instance have the same value.</summary>
+        <returns><see langword="true" /> if <paramref name="spanId" /> has the same hex value as the current instance; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -214,9 +214,9 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="obj" Type="System.Object" />
       </Parameters>
       <Docs>
-        <param name="obj">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="obj">The object to compare.</param>
+        <summary>the current instance and a specified object, which also must be an <see cref="T:System.Diagnostics.ActivitySpanId" /> instance, have the same value.</summary>
+        <returns><see langword="true" /> if <paramref name="obj" /> is an instance of <see cref="T:System.Diagnostics.ActivitySpanId" /> and has the same hex value as the current instance; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -237,8 +237,8 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Returns the hash code of the SpanId.</summary>
+        <returns>The hash code of the SpanId.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -262,10 +262,10 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="spandId2" Type="System.Diagnostics.ActivitySpanId" />
       </Parameters>
       <Docs>
-        <param name="spanId1">To be added.</param>
-        <param name="spandId2">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="spanId1">The first instance to compare.</param>
+        <param name="spandId2">The second instance to compare.</param>
+        <summary>Determines whether two specified <see cref="T:System.Diagnostics.ActivitySpanId" /> instances have the same value.</summary>
+        <returns><see langword="true" /> if the SpanId of <paramref name="spanId1" /> is the same as the SpanId of <paramref name="spandId2" />; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -289,10 +289,10 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="spandId2" Type="System.Diagnostics.ActivitySpanId" />
       </Parameters>
       <Docs>
-        <param name="spanId1">To be added.</param>
-        <param name="spandId2">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="spanId1">The first instance to compare.</param>
+        <param name="spandId2">The second instance to compare.</param>
+        <summary>Determine whether two specified <see cref="T:System.Diagnostics.ActivitySpanId" /> instances have unequal values.</summary>
+        <returns><see langword="true" /> if the SpanId of <paramref name="spanId1" /> is different from the SpanId of <paramref name="spandId2" />; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -341,4 +341,4 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>
diff --git a/xml/System.Diagnostics/ActivityTraceFlags.xml b/xml/System.Diagnostics/ActivityTraceFlags.xml
index 2bba38c2f4e..8091bf7a3ca 100644
--- a/xml/System.Diagnostics/ActivityTraceFlags.xml
+++ b/xml/System.Diagnostics/ActivityTraceFlags.xml
@@ -20,7 +20,9 @@
   <Docs>
     <summary>Specifies flags defined by the W3C standard that are associated with an activity.</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[  
+      <format type="text/markdown"><![CDATA[
+
+## Remarks
 
 An `ActivityTraceFflags` value is returned by the <xref:System.Diagnostics.Activity.ActivityTraceFlags?displayProperty=nameWithtype> property.
 
@@ -45,7 +47,7 @@ An `ActivityTraceFflags` value is returned by the <xref:System.Diagnostics.Activ
       </ReturnValue>
       <MemberValue>0</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>The activity has not been marked.</summary>
       </Docs>
     </Member>
     <Member MemberName="Recorded">
@@ -65,7 +67,7 @@ An `ActivityTraceFflags` value is returned by the <xref:System.Diagnostics.Activ
       </ReturnValue>
       <MemberValue>1</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>The activity (or more likely its parents) has been marked as useful to record.</summary>
       </Docs>
     </Member>
   </Members>
diff --git a/xml/System.Diagnostics/ActivityTraceId.xml b/xml/System.Diagnostics/ActivityTraceId.xml
index 9eaa9177edf..d9ec586eac1 100644
--- a/xml/System.Diagnostics/ActivityTraceId.xml
+++ b/xml/System.Diagnostics/ActivityTraceId.xml
@@ -22,6 +22,8 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
 
+## Remarks
+
 The `ActivityTraceId` structure reflects the format that the W3C standard requires for the ID of the entire trace. It consists of 16 bytes, typically represented as 32 hexadecimal characters. An `ActivityTraceId` is returned by the <xref:System.Diagnostics.Activity.TraceId?displayProperty=nameWithtype> property.
 
 Because an `ActivityTraceId` is a structure that contains 16 bytes, it can be passed easily by reference. `ActivityTraceId` contains methods for converting to and from its hexadecimal string representation, tries to avoid changing formats until it has to, and caches its string representation after it is created. It is mostly useful as an exchange type.
@@ -189,9 +191,9 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="traceId" Type="System.Diagnostics.ActivityTraceId" />
       </Parameters>
       <Docs>
-        <param name="traceId">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="traceId">The instance to compare.</param>
+        <summary>Determines whether the current instance and a specified <see cref="T:System.Diagnostics.ActivityTraceId" /> are equal.</summary>
+        <returns><see langword="true" /> if <paramref name="traceId" /> has the same hex value as the current instance; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -214,9 +216,9 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="obj" Type="System.Object" />
       </Parameters>
       <Docs>
-        <param name="obj">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="obj">The object to compare.</param>
+        <summary>Determines whether this instance and a specified object, which must also be an <see cref="T:System.Diagnostics.ActivityTraceId" /> instance, have the same value.</summary>
+        <returns><see langword="true" /> if <paramref name="obj" /> is an instance of <see cref="T:System.Diagnostics.ActivityTraceId" /> and has the same hex value as the current instance; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -237,8 +239,8 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Returns the hash code of the TraceId.</summary>
+        <returns>The hash code of the TraceId.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -262,11 +264,10 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="traceId2" Type="System.Diagnostics.ActivityTraceId" />
       </Parameters>
       <Docs>
-        <param name="traceId1">To be added.</param>
-        <param name="traceId2">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="traceId1">The first instance to compare.</param>
+        <param name="traceId2">The second instance to compare.</param>
+        <summary>Determines whether two specified <see cref="T:System.Diagnostics.ActivityTraceId" /> instances have the same value.</summary>
+        <returns><see langword="true" /> if the TraceId of <paramref name="traceId1" /> is the same as the TraceId of <paramref name="traceId2" />; otherwise, <see langword="false" />.</returns>
       </Docs>
     </Member>
     <Member MemberName="op_Inequality">
@@ -289,11 +290,10 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
         <Parameter Name="traceId2" Type="System.Diagnostics.ActivityTraceId" />
       </Parameters>
       <Docs>
-        <param name="traceId1">To be added.</param>
-        <param name="traceId2">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="traceId1">The first instance to compare.</param>
+        <param name="traceId2">The second instance to compare.</param>
+        <summary>Determines whether two specified <see cref="T:System.Diagnostics.ActivityTraceId" /> instances have the same value.</summary>
+        <returns><see langword="true" /> if the TraceId of <paramref name="traceId1" /> is different from the TraceId of <paramref name="traceId2" />; otherwise, <see langword="false" />.</returns>
       </Docs>
     </Member>
     <Member MemberName="ToHexString">
@@ -314,7 +314,7 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
       <Parameters />
       <Docs>
         <summary>Returns a 16-character hexadecimal string that represents this span ID.</summary>
-        <returns>The 32-character hecxadecimal string representation of this trace ID.</returns>
+        <returns>The 32-character hexadecimal string representation of this trace ID.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -335,10 +335,10 @@ The characters in <paramref name="idData" /> are not all lower-case hexadecimal
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>Returns a 32-aracter hexadecimal string that represents this trace ID.</summary>
+        <summary>Returns a 32-character hexadecimal string that represents this trace ID.</summary>
         <returns>The 32-character hecxadecimal string representation of this trace ID.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>
diff --git a/xml/System.Diagnostics/DiagnosticListener.xml b/xml/System.Diagnostics/DiagnosticListener.xml
index 0762047073d..3432a266db1 100644
--- a/xml/System.Diagnostics/DiagnosticListener.xml
+++ b/xml/System.Diagnostics/DiagnosticListener.xml
@@ -28,8 +28,13 @@
   <Docs>
     <summary>Provides an implementation of the abstract <see cref="T:System.Diagnostics.DiagnosticSource" /> class that represents a named place to which a source sends its information (events).</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[
-        
+      <format type="text/markdown">
+  <![CDATA[
+
+## Remarks
+
+`DiagnosticListener` is a NotificationSource, which means the returned result can be used to  log notifications, but it also has a <xref:System.Diagnostics.DiagnosticListener.Subscribe%2A> method so notifications can be forwarded arbitrarily. Thus, its job is to forward things from the producer to all the listeners (multi-casting). Generally, you should not be making your own <xref:System.Diagnostics.DiagnosticListener> but use the default, so that notifications are as public as possible.
+
 For more information on the <xref:System.Diagnostics.DiagnosticSource> and <xref:System.Diagnostics.DiagnosticListener> classes, see [DiagnosticSource User's Guide](https://github.com/dotnet/corefx/blob/d3942d4671919edb0cca6ddc1840190f524a809d/src/System.Diagnostics.DiagnosticSource/src/DiagnosticSourceUsersGuide.md).
 
         ]]></format>
@@ -59,13 +64,7 @@ For more information on the <xref:System.Diagnostics.DiagnosticSource> and <xref
       <Docs>
         <param name="name">The name of this <see cref="T:System.Diagnostics.DiagnosticListener" />.</param>
         <summary>Creates a new <see cref="T:System.Diagnostics.DiagnosticListener" />.</summary>
-        <remarks>
-          <format type="text/markdown"><![CDATA[  
-
-`DiagnosticListener` is a NotificationSource, which means the returned result can be used to  log notifications, but it also has a <xref:System.Diagnostics.DiagnosticListener.Subscribe%2A> method so notifications can be forwarded arbitrarily. Thus, its job is to forward things from the producer to all the listeners (multi-casting). Generally, you should not be making your own <see cref="T:System.Diagnostics.DiagnosticListener" /> but use the default, so that notifications are as public as possible.
- 
-         ]]></format>
-        </remarks>
+        <remarks>To be added.</remarks>
       </Docs>
     </Member>
     <Member MemberName="AllListeners">
@@ -269,9 +268,9 @@ If setup for the notification is expensive, you can call `IsEnabled` before perf
         <Parameter Name="payload" Type="System.Object" Index="1" FrameworkAlternate="netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="activity">To be added.</param>
-        <param name="payload">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="activity">The activity affected by an external event.</param>
+        <param name="payload">An object that represents the outgoing request.</param>
+        <summary>Invokes the OnActivityExport method of all the subscribers.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -294,9 +293,9 @@ If setup for the notification is expensive, you can call `IsEnabled` before perf
         <Parameter Name="payload" Type="System.Object" Index="1" FrameworkAlternate="netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="activity">To be added.</param>
-        <param name="payload">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="activity">The activity affected by an external event.</param>
+        <param name="payload">An object that represents the incoming request.</param>
+        <summary>Invokes the OnActivityImport method of all the subscribers.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Diagnostics/DiagnosticSource.xml b/xml/System.Diagnostics/DiagnosticSource.xml
index e52f0a3bd02..eb198237683 100644
--- a/xml/System.Diagnostics/DiagnosticSource.xml
+++ b/xml/System.Diagnostics/DiagnosticSource.xml
@@ -41,7 +41,7 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Initializes an instance of the <see cref="T:System.Diagnostics.DiagnosticSource" /> class.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -71,8 +71,7 @@
       <Docs>
         <param name="name">The name of the event being written.</param>
         <summary>Verifies if the notification event is enabled.</summary>
-        <returns>
-          <see langword="true" /> if the notification event is enabled, <see langword="false" /> otherwise.</returns>
+        <returns><see langword="true" /> if the notification event is enabled, <see langword="false" /> otherwise.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[
 
@@ -109,8 +108,7 @@ If there is expensive setup for the notification, you can call IsEnabled before
         <param name="arg1">An object that represents the additional context for IsEnabled. Consumers should expect to receive <see langword="null" /> which may indicate that producer called pure IsEnabled(string) to check if consumer wants to get notifications for such events at all. Based on that, producer may call IsEnabled(string, object, object) again with non-<see langword="null" /> context.</param>
         <param name="arg2">Optional. An object that represents the additional context for IsEnabled. <see langword="null" /> by default. Consumers should expect to receive <see langword="null" /> which may indicate that producer called pure IsEnabled(string) or producer passed all necessary context in <paramref name="arg1" />.</param>
         <summary>Verifies it the notification event is enabled.</summary>
-        <returns>
-          <see langword="true" /> if the notification event is enabled, <see langword="false" /> otherwise.</returns>
+        <returns><see langword="true" /> if the notification event is enabled, <see langword="false" /> otherwise.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[
           
@@ -139,20 +137,20 @@ If there is expensive setup for the notification, you can call this method and p
         <Parameter Name="payload" Type="System.Object" Index="1" FrameworkAlternate="netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="activity">To be added.</param>
-        <param name="payload">To be added.</param>
+        <param name="activity">The activity affected by an external event.</param>
+        <param name="payload">An object that represents the outgoing request.</param>
         <summary>Transfers state from an activity to some event or operation, such as an outgoing HTTP request, that will occur outside the process.</summary>
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
-If an instumentation site is at a location where activities leave the process (such as outgoing HTTP requests), that site will want to transfer state from the activity to the outgoing request.
+If an instrumentation site is at a location where activities leave the process (such as outgoing HTTP requests), that site will want to transfer state from the activity to the outgoing request.
 
-To the extent possible, this should be done by the instrumenation site, because there is a contract between an <xref:System.Diagnostics.Activity> and the ougoing request logic at the instrumentation site.   However, the instrumenation site can't handle policy (for example, whether activity information should be disabled or written in an older format for compatibility reasons).
+To the extent possible, this should be done by the instrumentation site, because there is a contract between an <xref:System.Diagnostics.Activity> and the ougoing request logic at the instrumentation site.   However, the instrumentation site can't handle policy (for example, whether activity information should be disabled or written in an older format for compatibility reasons).
 For this, the instrumentation site needs to call back out to the logging system and ask it to resolve policy. This is the purpose of the `OnActivityExport` method.
 
 The `OnActivityExport` method is given the <xref:System.Diagnostics.Activity> as well as a payload object that represents the outgoing request. A <xref:System.Diagnostics.DiagnosticSource> subscriber then has the ability to update the outgoing request before it is sent.
  
-Note that this method is rarely used at instrumentation sites (only those sites that are on an outgoing boundary of the process).   Moreover, typically the default policy that the instrumenation site performs (for example, to transfer all activity state in a 
+Note that this method is rarely used at instrumentation sites (only those sites that are on an outgoing boundary of the process).   Moreover, typically the default policy that the instrumentation site performs (for example, to transfer all activity state in a 
 particular outgoing convention) is likely to be fine. This method is only for cases where that is a problem. Thus, this method should be used very rarely and is mostly here for symetry with `OnActivityImport` and future-proofing.
 
 Note that `payload` is typed as an <xref:System.Object> here, but any particular instrumentation site and subscriber should know the type of the payload and thus cast and decode it if necessary.
@@ -186,7 +184,7 @@ Note that `payload` is typed as an <xref:System.Object> here, but any particular
         <remarks>
           <format type="text/markdown"><![CDATA[  
 
-If an instumentation site creates a new activity in response to some event outside the process, such as an incomming HTTP request), the `OnActivityImport` method allows that site will want to create a new activity and transfer state from the incoming request to the activity. 
+If an instrumentation site creates a new activity in response to some event outside the process, such as an incomming HTTP request), the `OnActivityImport` method allows that site will want to create a new activity and transfer state from the incoming request to the activity. 
 
 To the extent possible, this should be done by the instrumentation site, because there is a contract between the <xref:System.Diagnostics.Activity> and the incomming request logic at the instrumentation site.   However, the instrumentation site can't handle policy. (For example, if sampling is done, exactly which requests should be sampled?) In these cases, the instrumentation site needs to call back out to the logging system and ask it to resolve policy (for example, to decide if the activity's "sampling" bit should be set). This is the purpose of the `OnActivityImport` method. It is given the activity as well as a payload object that represents the incomming request. The subscribers to the <xref:System.Diagnostics.DiagnosticSource> then have the opportunity to update this activity as desired.