diff --git a/xml/System.Collections.Concurrent/ConcurrentDictionary`2+AlternateLookup`1.xml b/xml/System.Collections.Concurrent/ConcurrentDictionary`2+AlternateLookup`1.xml
index 9d4fbcec8f0..b1fc4e7d9bb 100644
--- a/xml/System.Collections.Concurrent/ConcurrentDictionary`2+AlternateLookup`1.xml
+++ b/xml/System.Collections.Concurrent/ConcurrentDictionary`2+AlternateLookup`1.xml
@@ -176,7 +176,8 @@
           <para>otherwise, the default value for the type of the value parameter.</para>
         </param>
         <summary>Gets the value associated with the specified alternate key.</summary>
-        <returns>To be added.</returns>
+        <returns>
+          <see langword="true" /> if an entry was found; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentNullException">
           <paramref name="key" /> is <see langword="null" />.</exception>
@@ -213,7 +214,8 @@
           <para>otherwise, the default value for the type of the value parameter.</para>
         </param>
         <summary>Gets the value associated with the specified alternate key.</summary>
-        <returns>To be added.</returns>
+        <returns>
+          <see langword="true" /> if an entry was found; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentNullException">
           <paramref name="key" /> is <see langword="null" />.</exception>
diff --git a/xml/System.Collections.Concurrent/ConcurrentDictionary`2.xml b/xml/System.Collections.Concurrent/ConcurrentDictionary`2.xml
index 4e2f31eb635..d73132de058 100644
--- a/xml/System.Collections.Concurrent/ConcurrentDictionary`2.xml
+++ b/xml/System.Collections.Concurrent/ConcurrentDictionary`2.xml
@@ -2704,11 +2704,18 @@ This member is an explicit interface member implementation. It can be used only
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TAlternateKey">To be added.</typeparam>
-        <param name="lookup">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TAlternateKey">The alternate type of a key for performing lookups.</typeparam>
+        <param name="lookup">The created lookup instance when the method returns <see langword="true" />, or a default instance that should not be used if the method returns <see langword="false" />.</param>
+        <summary>
+          Gets an instance of a type that may be used to perform operations on a <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2"/> 
+          using a <typeparamref name="TAlternateKey"/> as a key instead of a <typeparamref name="TKey"/>.
+        </summary>
+        <returns>
+          <see langword="true" /> if a lookup could be created; otherwise, <see langword="false" />.</returns>
+        <remarks>
+          This instance must be using a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2" /> with 
+          <typeparamref name="TAlternateKey"/> and <typeparamref name="TKey"/>. If it doesn't, the method will return <see langword="false" />. 
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="TryGetValue">
diff --git a/xml/System.Collections.Frozen/FrozenDictionary`2+AlternateLookup`1.xml b/xml/System.Collections.Frozen/FrozenDictionary`2+AlternateLookup`1.xml
index dabf7845286..94eb94600dd 100644
--- a/xml/System.Collections.Frozen/FrozenDictionary`2+AlternateLookup`1.xml
+++ b/xml/System.Collections.Frozen/FrozenDictionary`2+AlternateLookup`1.xml
@@ -157,7 +157,8 @@
           <para>otherwise, the default value for the type of the value parameter.</para>
         </param>
         <summary>Gets the value associated with the specified alternate key.</summary>
-        <returns>To be added.</returns>
+        <returns>
+          <see langword="true" /> if an entry was found; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentNullException">
           <paramref name="key" /> is <see langword="null" />.</exception>
diff --git a/xml/System.Collections.Frozen/FrozenDictionary`2.xml b/xml/System.Collections.Frozen/FrozenDictionary`2.xml
index 5b3c8c03a83..b1ec85ac651 100644
--- a/xml/System.Collections.Frozen/FrozenDictionary`2.xml
+++ b/xml/System.Collections.Frozen/FrozenDictionary`2.xml
@@ -1221,11 +1221,18 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TAlternateKey">To be added.</typeparam>
-        <param name="lookup">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TAlternateKey">The alternate type of a key for performing lookups.</typeparam>
+        <param name="lookup">The created lookup instance when the method returns <see langword="true" />, or a default instance that should not be used if the method returns <see langword="false" />.</param>
+        <summary>
+          Gets an instance of a type that may be used to perform operations on a <see cref="T:System.Collections.Frozen.FrozenDictionary`2"/>
+          using a <typeparamref name="TAlternateKey"/> as a key instead of a <typeparamref name="TKey"/>.
+        </summary>
+        <returns>
+          <see langword="true" /> if a lookup could be created; otherwise, <see langword="false" />.</returns>
+        <remarks>
+          This instance must be using a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2"/> with
+          <typeparamref name="TAlternateKey"/> and <typeparamref name="TKey"/>. If it doesn't, the method will return <see langword="false" />.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="TryGetValue">
@@ -1263,8 +1270,7 @@
         <param name="key">The key of the value to get.</param>
         <param name="value">When this method returns, contains the value associated with the specified key, if the key is found; otherwise, the default value for the type of <paramref name="value" />.</param>
         <summary>Gets the value associated with the specified key.</summary>
-        <returns>
-          <see langword="true" /> if the dictionary contains an element with the specified key; otherwise, <see langword="false" />.</returns>
+        <returns><see langword="true" /> if the dictionary contains an element with the specified key; otherwise, <see langword="false" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Collections.Frozen/FrozenSet`1.xml b/xml/System.Collections.Frozen/FrozenSet`1.xml
index 586ca878080..d3eda2433f1 100644
--- a/xml/System.Collections.Frozen/FrozenSet`1.xml
+++ b/xml/System.Collections.Frozen/FrozenSet`1.xml
@@ -962,11 +962,18 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TAlternate">To be added.</typeparam>
-        <param name="lookup">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TAlternate">The alternate type of a key for performing lookups.</typeparam>
+        <param name="lookup">The created lookup instance when the method returns <see langword="true" />, or a default instance that should not be used if the method returns <see langword="false" />.</param>
+        <summary>
+          Gets an instance of a type that may be used to perform operations on a <see cref="T:System.Collections.Frozen.FrozenSet`1"/>
+          using a <typeparamref name="TAlternate"/> instead of a <typeparamref name="T"/>.
+        </summary>
+        <returns>
+          <see langword="true" /> if a lookup could be created; otherwise, <see langword="false" />.</returns>
+        <remarks>
+          This instance must be using a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2"/> with
+          <typeparamref name="TAlternate"/> and <typeparamref name="T"/>. If it doesn't, the method will return <see langword="false" />.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="TryGetValue">
diff --git a/xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml b/xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml
index 551a6db7562..e268bb3b9d4 100644
--- a/xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml
+++ b/xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml
@@ -97,7 +97,7 @@
         <Parameter Name="key" Type="TKey" />
       </Parameters>
       <Docs>
-        <param name="key">To be added.</param>
+        <param name="key">They key to the location in the collection.</param>
         <summary>Determines whether the <see cref="T:System.Collections.Generic.ICollection`1" /> contains a specific value.</summary>
         <returns>
           <see langword="true" /> if <paramref name="item" /> is found in the <see cref="T:System.Collections.Generic.ICollection`1" />; otherwise, <see langword="false" />.</returns>
diff --git a/xml/System.Linq/Enumerable.xml b/xml/System.Linq/Enumerable.xml
index 34c475eb5a9..8740ee6b85f 100644
--- a/xml/System.Linq/Enumerable.xml
+++ b/xml/System.Linq/Enumerable.xml
@@ -393,17 +393,19 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TSource">To be added.</typeparam>
-        <typeparam name="TKey">To be added.</typeparam>
-        <typeparam name="TAccumulate">To be added.</typeparam>
-        <param name="source">To be added.</param>
-        <param name="keySelector">To be added.</param>
-        <param name="seedSelector">To be added.</param>
-        <param name="func">To be added.</param>
-        <param name="keyComparer">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
+        <typeparam name="TKey">The type of the key returned by <paramref name="keySelector" />.</typeparam>
+        <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>
+        <param name="source">An <see cref="T:System.Collections.Generic.IEnumerable`1" /> to aggregate over.</param>
+        <param name="keySelector">A function to extract the key for each element.</param>
+        <param name="seedSelector">A factory for the initial accumulator value.</param>
+        <param name="func">An accumulator function to be invoked on each element.</param>
+        <param name="keyComparer">An <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> to compare keys with.</param>
+        <summary>Applies an accumulator function over a sequence, grouping results by key.</summary>
+        <returns>An enumerable containing the aggregates corresponding to each key deriving from <paramref name="source" />.</returns>
+        <remarks>
+          This method is comparable to the <see cref="M:System.Linq.Enumerable.GroupBy``2(System.Collections.Generic.IEnumerable{``0},System.Func{``0,``1})" /> methods where each grouping is being aggregated into a single value as opposed to allocating a collection for each group.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="AggregateBy&lt;TSource,TKey,TAccumulate&gt;">
@@ -466,17 +468,19 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TSource">To be added.</typeparam>
-        <typeparam name="TKey">To be added.</typeparam>
-        <typeparam name="TAccumulate">To be added.</typeparam>
-        <param name="source">To be added.</param>
-        <param name="keySelector">To be added.</param>
-        <param name="seed">To be added.</param>
-        <param name="func">To be added.</param>
-        <param name="keyComparer">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
+        <typeparam name="TKey">The type of the key returned by <paramref name="keySelector" />.</typeparam>
+        <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>
+        <param name="source">An <see cref="T:System.Collections.Generic.IEnumerable`1" /> to aggregate over.</param>
+        <param name="keySelector">A function to extract the key for each element.</param>
+        <param name="seed">The initial accumulator value.</param>
+        <param name="func">An accumulator function to be invoked on each element.</param>
+        <param name="keyComparer">An <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> to compare keys with.</param>
+        <summary>Applies an accumulator function over a sequence, grouping results by key.</summary>
+        <returns>An enumerable containing the aggregates corresponding to each key deriving from <paramref name="source" />.</returns>
+        <remarks>
+          This method is comparable to the <see cref="M:System.Linq.Enumerable.GroupBy``2(System.Collections.Generic.IEnumerable{``0},System.Func{``0,``1})" /> methods where each grouping is being aggregated into a single value as opposed to allocating a collection for each group.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="All&lt;TSource&gt;">
@@ -2893,13 +2897,13 @@ Each chunk except the last one will be of size `size`. The last chunk will conta
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TSource">To be added.</typeparam>
-        <typeparam name="TKey">To be added.</typeparam>
-        <param name="source">To be added.</param>
-        <param name="keySelector">To be added.</param>
-        <param name="keyComparer">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <typeparam name="TSource">The type of elements of <paramref name="source" />.</typeparam>
+        <typeparam name="TKey">The type of the key returned by <paramref name="keySelector" />.</typeparam>
+        <param name="source">A sequence that contains elements to be counted.</param>
+        <param name="keySelector">A function to extract the key for each element.</param>
+        <param name="keyComparer">An <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> to compare keys with.</param>
+        <summary>Returns the count of elements in the source sequence grouped by key.</summary>
+        <returns>An enumerable containing the frequencies of each key occurrence in <paramref name="source" />.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -5677,7 +5681,7 @@ Only unique elements are returned.
         <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
         <param name="source">The source enumerable providing the elements.</param>
         <summary>Returns an enumerable that incorporates the element's index into a tuple.</summary>
-        <returns>To be added.</returns>
+        <returns>An enumerable that incorporates each element index into a tuple.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentNullException">
           <paramref name="source" /> is <see langword="null" />.</exception>
diff --git a/xml/System.Linq/Queryable.xml b/xml/System.Linq/Queryable.xml
index 9dabc0bb05a..db212ff3c93 100644
--- a/xml/System.Linq/Queryable.xml
+++ b/xml/System.Linq/Queryable.xml
@@ -421,17 +421,19 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TSource">To be added.</typeparam>
-        <typeparam name="TKey">To be added.</typeparam>
-        <typeparam name="TAccumulate">To be added.</typeparam>
-        <param name="source">To be added.</param>
-        <param name="keySelector">To be added.</param>
-        <param name="seedSelector">To be added.</param>
-        <param name="func">To be added.</param>
-        <param name="keyComparer">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
+        <typeparam name="TKey">The type of the key returned by <paramref name="keySelector" />.</typeparam>
+        <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>
+        <param name="source">An <see cref="T:System.Linq.IQueryable`1" /> to aggregate over.</param>
+        <param name="keySelector">A function to extract the key for each element.</param>
+        <param name="seedSelector">A factory for the initial accumulator value.</param>
+        <param name="func">An accumulator function to be invoked on each element.</param>
+        <param name="keyComparer">An <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> to compare keys with.</param>
+        <summary>Applies an accumulator function over a sequence, grouping results by key.</summary>
+        <returns>An enumerable containing the aggregates corresponding to each key deriving from <paramref name="source" />.</returns>
+        <remarks>
+          This method is comparable to the <see cref="M:System.Linq.Queryable.GroupBy``2(System.Linq.IQueryable{``0},System.Linq.Expressions.Expression{System.Func{``0,``1}})" /> methods where each grouping is being aggregated into a single value as opposed to allocating a collection for each group.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="AggregateBy&lt;TSource,TKey,TAccumulate&gt;">
@@ -494,17 +496,19 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TSource">To be added.</typeparam>
-        <typeparam name="TKey">To be added.</typeparam>
-        <typeparam name="TAccumulate">To be added.</typeparam>
-        <param name="source">To be added.</param>
-        <param name="keySelector">To be added.</param>
-        <param name="seed">To be added.</param>
-        <param name="func">To be added.</param>
-        <param name="keyComparer">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
+        <typeparam name="TKey">The type of the key returned by <paramref name="keySelector" />.</typeparam>
+        <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>
+        <param name="source">An <see cref="T:System.Linq.IQueryable`1" /> to aggregate over.</param>
+        <param name="keySelector">A function to extract the key for each element.</param>
+        <param name="seed">The initial accumulator value.</param>
+        <param name="func">An accumulator function to be invoked on each element.</param>
+        <param name="keyComparer">An <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> to compare keys with.</param>
+        <summary>Applies an accumulator function over a sequence, grouping results by key.</summary>
+        <returns>An enumerable containing the aggregates corresponding to each key deriving from <paramref name="source" />.</returns>
+        <remarks>
+          This method is comparable to the <see cref="M:System.Linq.Queryable.GroupBy``2(System.Linq.IQueryable{``0},System.Linq.Expressions.Expression{System.Func{``0,``1}})" /> methods where each grouping is being aggregated into a single value as opposed to allocating a collection for each group.
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="All&lt;TSource&gt;">
@@ -5834,7 +5838,7 @@ The last chunk will contain the remaining elements and may be of a smaller size.
         <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
         <param name="source">An <see cref="T:System.Linq.IQueryable`1" /> to return an element from.</param>
         <summary>Return index and the associated item.</summary>
-        <returns>To be added.</returns>
+        <returns>An enumerable that incorporates each element index into a tuple.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentNullException">
           <paramref name="source" /> is <see langword="null" />.</exception>