diff --git a/Perspex.Base/Collections/IPerspexList.cs b/Perspex.Base/Collections/IPerspexList.cs
index 04e9c2f25e..3684f0fb49 100644
--- a/Perspex.Base/Collections/IPerspexList.cs
+++ b/Perspex.Base/Collections/IPerspexList.cs
@@ -6,15 +6,31 @@
 
 namespace Perspex.Collections
 {
-    using System.Collections;
     using System.Collections.Generic;
 
+    /// <summary>
+    /// A notiftying list.
+    /// </summary>
+    /// <typeparam name="T">The type of the items in the list.</typeparam>
     public interface IPerspexList<T> : IList<T>, IPerspexReadOnlyList<T>
     {
+        /// <summary>
+        /// Adds multiple items to the collection.
+        /// </summary>
+        /// <param name="items">The items.</param>
         void AddRange(IEnumerable<T> items);
 
+        /// <summary>
+        /// Inserts multiple items at the specified index.
+        /// </summary>
+        /// <param name="index">The index.</param>
+        /// <param name="items">The items.</param>
         void InsertRange(int index, IEnumerable<T> items);
 
+        /// <summary>
+        /// Removes multiple items from the collection.
+        /// </summary>
+        /// <param name="items">The items.</param>
         void RemoveAll(IEnumerable<T> items);
     }
 }
\ No newline at end of file
diff --git a/Perspex.Base/Collections/IPerspexReadOnlyList.cs b/Perspex.Base/Collections/IPerspexReadOnlyList.cs
index 454467ce3c..cfbb18b16e 100644
--- a/Perspex.Base/Collections/IPerspexReadOnlyList.cs
+++ b/Perspex.Base/Collections/IPerspexReadOnlyList.cs
@@ -10,6 +10,10 @@ namespace Perspex.Collections
     using System.Collections.Specialized;
     using System.ComponentModel;
 
+    /// <summary>
+    /// A read-only notiftying list.
+    /// </summary>
+    /// <typeparam name="T">The type of the items in the list.</typeparam>
     public interface IPerspexReadOnlyList<out T> : IReadOnlyList<T>, INotifyCollectionChanged, INotifyPropertyChanged
     {
     }
diff --git a/Perspex.Base/Platform/PlatformHandle.cs b/Perspex.Base/Platform/PlatformHandle.cs
index b5d2c0daf6..4831dad514 100644
--- a/Perspex.Base/Platform/PlatformHandle.cs
+++ b/Perspex.Base/Platform/PlatformHandle.cs
@@ -8,16 +8,32 @@ namespace Perspex.Platform
 {
     using System;
 
+    /// <summary>
+    /// Represents a platform-specific handle.
+    /// </summary>
     public class PlatformHandle : IPlatformHandle
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PlatformHandle"/> class.
+        /// </summary>
+        /// <param name="handle">The handle.</param>
+        /// <param name="descriptor">
+        /// An optional string that describes what <paramref name="handle"/> represents.
+        /// </param>
         public PlatformHandle(IntPtr handle, string descriptor)
         {
             this.Handle = handle;
             this.HandleDescriptor = descriptor;
         }
 
-        public IntPtr Handle { get; private set; }
+        /// <summary>
+        /// Gets the handle.
+        /// </summary>
+        public IntPtr Handle { get; }
 
-        public string HandleDescriptor { get; private set; }
+        /// <summary>
+        /// Gets an optional string that describes what <see cref="Handle"/> represents.
+        /// </summary>
+        public string HandleDescriptor { get; }
     }
 }
diff --git a/Perspex.Base/Reactive/PerspexObservable.cs b/Perspex.Base/Reactive/PerspexObservable.cs
index 1b11e18959..59376a79ac 100644
--- a/Perspex.Base/Reactive/PerspexObservable.cs
+++ b/Perspex.Base/Reactive/PerspexObservable.cs
@@ -10,10 +10,19 @@ namespace Perspex.Reactive
     using System.Reactive;
     using System.Reactive.Disposables;
 
+    /// <summary>
+    /// An <see cref="IObservable{T}"/> with an additional description.
+    /// </summary>
+    /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
     public sealed class PerspexObservable<T> : ObservableBase<T>, IDescription
     {
         private readonly Func<IObserver<T>, IDisposable> subscribe;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PerspexObservable{T}"/> class.
+        /// </summary>
+        /// <param name="subscribe">The subscribe function.</param>
+        /// <param name="description">The description of the observable.</param>
         public PerspexObservable(Func<IObserver<T>, IDisposable> subscribe, string description)
         {
             if (subscribe == null)
@@ -25,8 +34,12 @@ namespace Perspex.Reactive
             this.Description = description;
         }
 
+        /// <summary>
+        /// Gets the description of the observable.
+        /// </summary>
         public string Description { get; }
 
+        /// <inheritdoc/>
         protected override IDisposable SubscribeCore(IObserver<T> observer)
         {
             return this.subscribe(observer) ?? Disposable.Empty;