diff --git a/csharp/src/Google.Protobuf/ByteString.cs b/csharp/src/Google.Protobuf/ByteString.cs
index cf5468d..2aa6248 100644
--- a/csharp/src/Google.Protobuf/ByteString.cs
+++ b/csharp/src/Google.Protobuf/ByteString.cs
@@ -105,23 +105,35 @@
             get { return bytes.Length; }
         }
 
+        /// <summary>
+        /// Returns <c>true</c> if this byte string is empty, <c>false</c> otherwise.
+        /// </summary>
         public bool IsEmpty
         {
             get { return Length == 0; }
         }
 
+        /// <summary>
+        /// Converts this <see cref="ByteString"/> into a byte array.
+        /// </summary>
+        /// <remarks>The data is copied - changes to the returned array will not be reflected in this <c>ByteString</c>.</remarks>
+        /// <returns>A byte array with the same data as this <c>ByteString</c>.</returns>
         public byte[] ToByteArray()
         {
             return (byte[]) bytes.Clone();
         }
 
+        /// <summary>
+        /// Converts this <see cref="ByteString"/> into a standard base64 representation.
+        /// </summary>
+        /// <returns>A base64 representation of this <c>ByteString</c>.</returns>
         public string ToBase64()
         {
             return Convert.ToBase64String(bytes);
         }
 
         /// <summary>
-        /// Constructs a ByteString from the Base64 Encoded String.
+        /// Constructs a <see cref="ByteString" /> from the Base64 Encoded String.
         /// </summary>
         public static ByteString FromBase64(string bytes)
         {
@@ -131,7 +143,7 @@
         }
 
         /// <summary>
-        /// Constructs a ByteString from the given array. The contents
+        /// Constructs a <see cref="ByteString" /> from the given array. The contents
         /// are copied, so further modifications to the array will not
         /// be reflected in the returned ByteString.
         /// This method can also be invoked in <c>ByteString.CopyFrom(0xaa, 0xbb, ...)</c> form
@@ -143,7 +155,7 @@
         }
 
         /// <summary>
-        /// Constructs a ByteString from a portion of a byte array.
+        /// Constructs a <see cref="ByteString" /> from a portion of a byte array.
         /// </summary>
         public static ByteString CopyFrom(byte[] bytes, int offset, int count)
         {
@@ -153,7 +165,7 @@
         }
 
         /// <summary>
-        /// Creates a new ByteString by encoding the specified text with
+        /// Creates a new <see cref="ByteString" /> by encoding the specified text with
         /// the given encoding.
         /// </summary>
         public static ByteString CopyFrom(string text, Encoding encoding)
@@ -162,7 +174,7 @@
         }
 
         /// <summary>
-        /// Creates a new ByteString by encoding the specified text in UTF-8.
+        /// Creates a new <see cref="ByteString" /> by encoding the specified text in UTF-8.
         /// </summary>
         public static ByteString CopyFromUtf8(string text)
         {
@@ -177,21 +189,46 @@
             get { return bytes[index]; }
         }
 
+        /// <summary>
+        /// Converts this <see cref="ByteString"/> into a string by applying the given encoding.
+        /// </summary>
+        /// <remarks>
+        /// This method should only be used to convert binary data which was the result of encoding
+        /// text with the given encoding.
+        /// </remarks>
+        /// <param name="encoding">The encoding to use to decode the binary data into text.</param>
+        /// <returns>The result of decoding the binary data with the given decoding.</returns>
         public string ToString(Encoding encoding)
         {
             return encoding.GetString(bytes, 0, bytes.Length);
         }
 
+        /// <summary>
+        /// Converts this <see cref="ByteString"/> into a string by applying the UTF-8 encoding.
+        /// </summary>
+        /// <remarks>
+        /// This method should only be used to convert binary data which was the result of encoding
+        /// text with UTF-8.
+        /// </remarks>
+        /// <returns>The result of decoding the binary data with the given decoding.</returns>
         public string ToStringUtf8()
         {
             return ToString(Encoding.UTF8);
         }
 
+        /// <summary>
+        /// Returns an iterator over the bytes in this <see cref="ByteString"/>.
+        /// </summary>
+        /// <returns>An iterator over the bytes in this object.</returns>
         public IEnumerator<byte> GetEnumerator()
         {
             return ((IEnumerable<byte>) bytes).GetEnumerator();
         }
 
+        /// <summary>
+        /// Returns an iterator over the bytes in this <see cref="ByteString"/>.
+        /// </summary>
+        /// <returns>An iterator over the bytes in this object.</returns>
         IEnumerator IEnumerable.GetEnumerator()
         {
             return GetEnumerator();
@@ -206,6 +243,12 @@
             return new CodedInputStream(bytes);
         }
 
+        /// <summary>
+        /// Compares two byte strings for equality.
+        /// </summary>
+        /// <param name="lhs">The first byte string to compare.</param>
+        /// <param name="rhs">The second byte string to compare.</param>
+        /// <returns><c>true</c> if the byte strings are equal; false otherwise.</returns>
         public static bool operator ==(ByteString lhs, ByteString rhs)
         {
             if (ReferenceEquals(lhs, rhs))
@@ -230,6 +273,12 @@
             return true;
         }
 
+        /// <summary>
+        /// Compares two byte strings for inequality.
+        /// </summary>
+        /// <param name="lhs">The first byte string to compare.</param>
+        /// <param name="rhs">The second byte string to compare.</param>
+        /// <returns><c>false</c> if the byte strings are equal; true otherwise.</returns>
         public static bool operator !=(ByteString lhs, ByteString rhs)
         {
             return !(lhs == rhs);
@@ -237,11 +286,21 @@
 
         // TODO(jonskeet): CopyTo if it turns out to be required
 
+        /// <summary>
+        /// Compares this byte string with another object.
+        /// </summary>
+        /// <param name="obj">The object to compare this with.</param>
+        /// <returns><c>true</c> if <paramref name="obj"/> refers to an equal <see cref="ByteString"/>; <c>false</c> otherwise.</returns>
         public override bool Equals(object obj)
         {
             return this == (obj as ByteString);
         }
 
+        /// <summary>
+        /// Returns a hash code for this object. Two equal byte strings
+        /// will return the same hash code.
+        /// </summary>
+        /// <returns>A hash code for this object.</returns>
         public override int GetHashCode()
         {
             int ret = 23;
@@ -252,6 +311,11 @@
             return ret;
         }
 
+        /// <summary>
+        /// Compares this byte string with another.
+        /// </summary>
+        /// <param name="other">The <see cref="ByteString"/> to compare this with.</param>
+        /// <returns><c>true</c> if <paramref name="other"/> refers to an equal byte string; <c>false</c> otherwise.</returns>
         public bool Equals(ByteString other)
         {
             return this == other;
diff --git a/csharp/src/Google.Protobuf/CodedInputStream.cs b/csharp/src/Google.Protobuf/CodedInputStream.cs
index f2e1d66..a1abfcb 100644
--- a/csharp/src/Google.Protobuf/CodedInputStream.cs
+++ b/csharp/src/Google.Protobuf/CodedInputStream.cs
@@ -66,7 +66,7 @@
 
         internal const int DefaultRecursionLimit = 64;
         internal const int DefaultSizeLimit = 64 << 20; // 64MB
-        public const int BufferSize = 4096;
+        internal const int BufferSize = 4096;
 
         /// <summary>
         /// The total number of bytes read before the current buffer. The
diff --git a/csharp/src/Google.Protobuf/CodedOutputStream.cs b/csharp/src/Google.Protobuf/CodedOutputStream.cs
index b084c14..08ea700 100644
--- a/csharp/src/Google.Protobuf/CodedOutputStream.cs
+++ b/csharp/src/Google.Protobuf/CodedOutputStream.cs
@@ -297,6 +297,10 @@
             WriteInt32(value);
         }
 
+        /// <summary>
+        /// Writes an sfixed32 value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write.</param>
         public void WriteSFixed32(int value)
         {
             WriteRawLittleEndian32((uint) value);
@@ -649,6 +653,9 @@
             }
         }
 
+        /// <summary>
+        /// Flushes any buffered data to the underlying stream (if there is one).
+        /// </summary>
         public void Flush()
         {
             if (output != null)
diff --git a/csharp/src/Google.Protobuf/Collections/MapField.cs b/csharp/src/Google.Protobuf/Collections/MapField.cs
index fc94fd5..fed3d06 100644
--- a/csharp/src/Google.Protobuf/Collections/MapField.cs
+++ b/csharp/src/Google.Protobuf/Collections/MapField.cs
@@ -42,14 +42,14 @@
     /// <summary>
     /// Representation of a map field in a Protocol Buffer message.
     /// </summary>
+    /// <typeparam name="TKey">Key type in the map. Must be a type supported by Protocol Buffer map keys.</typeparam>
+    /// <typeparam name="TValue">Value type in the map. Must be a type supported by Protocol Buffers.</typeparam>
     /// <remarks>
     /// This implementation preserves insertion order for simplicity of testing
     /// code using maps fields. Overwriting an existing entry does not change the
     /// position of that entry within the map. Equality is not order-sensitive.
-    /// For string keys, the equality comparison is provided by <see cref="StringComparer.Ordinal"/>.
+    /// For string keys, the equality comparison is provided by <see cref="StringComparer.Ordinal" />.
     /// </remarks>
-    /// <typeparam name="TKey">Key type in the map. Must be a type supported by Protocol Buffer map keys.</typeparam>
-    /// <typeparam name="TValue">Value type in the map. Must be a type supported by Protocol Buffers.</typeparam>
     public sealed class MapField<TKey, TValue> : IDeepCloneable<MapField<TKey, TValue>>, IDictionary<TKey, TValue>, IEquatable<MapField<TKey, TValue>>, IDictionary
     {
         // TODO: Don't create the map/list until we have an entry. (Assume many maps will be empty.)
@@ -81,6 +81,12 @@
             this.allowNullValues = allowNullValues;
         }
 
+        /// <summary>
+        /// Creates a deep clone of this object.
+        /// </summary>
+        /// <returns>
+        /// A deep clone of this object.
+        /// </returns>
         public MapField<TKey, TValue> Clone()
         {
             var clone = new MapField<TKey, TValue>(allowNullValues);
@@ -100,6 +106,15 @@
             return clone;
         }
 
+        /// <summary>
+        /// Adds the specified key/value pair to the map.
+        /// </summary>
+        /// <remarks>
+        /// This operation fails if the key already exists in the map. To replace an existing entry, use the indexer.
+        /// </remarks>
+        /// <param name="key">The key to add</param>
+        /// <param name="value">The value to add.</param>
+        /// <exception cref="System.ArgumentException">The given key already exists in map.</exception>
         public void Add(TKey key, TValue value)
         {
             // Validation of arguments happens in ContainsKey and the indexer
@@ -110,12 +125,22 @@
             this[key] = value;
         }
 
+        /// <summary>
+        /// Determines whether the specified key is present in the map.
+        /// </summary>
+        /// <param name="key">The key to check.</param>
+        /// <returns><c>true</c> if the map contains the given key; <c>false</c> otherwise.</returns>
         public bool ContainsKey(TKey key)
         {
             Preconditions.CheckNotNullUnconstrained(key, "key");
             return map.ContainsKey(key);
         }
 
+        /// <summary>
+        /// Removes the entry identified by the given key from the map.
+        /// </summary>
+        /// <param name="key">The key indicating the entry to remove from the map.</param>
+        /// <returns><c>true</c> if the map contained the given key before the entry was removed; <c>false</c> otherwise.</returns>
         public bool Remove(TKey key)
         {
             Preconditions.CheckNotNullUnconstrained(key, "key");
@@ -132,6 +157,14 @@
             }
         }
 
+        /// <summary>
+        /// Gets the value associated with the specified key.
+        /// </summary>
+        /// <param name="key">The key whose value to get.</param>
+        /// <param name="value">When this method returns, the value associated with the specified key, if the key is found;
+        /// otherwise, the default value for the type of the <paramref name="value"/> parameter.
+        /// This parameter is passed uninitialized.</param>
+        /// <returns><c>true</c> if the map contains an element with the specified key; otherwise, <c>false</c>.</returns>
         public bool TryGetValue(TKey key, out TValue value)
         {
             LinkedListNode<KeyValuePair<TKey, TValue>> node;
@@ -147,6 +180,13 @@
             }
         }
 
+        /// <summary>
+        /// Gets or sets the value associated with the specified key.
+        /// </summary>
+        /// <param name="key">The key of the value to get or set.</param>
+        /// <exception cref="KeyNotFoundException">The property is retrieved and key does not exist in the collection.</exception>
+        /// <returns>The value associated with the specified key. If the specified key is not found,
+        /// a get operation throws a <see cref="KeyNotFoundException"/>, and a set operation creates a new element with the specified key.</returns>
         public TValue this[TKey key]
         {
             get
@@ -182,9 +222,21 @@
         }
 
         // TODO: Make these views?
+
+        /// <summary>
+        /// Gets a collection containing the keys in the map.
+        /// </summary>
         public ICollection<TKey> Keys { get { return list.Select(t => t.Key).ToList(); } }
+
+        /// <summary>
+        /// Gets a collection containing the values in the map.
+        /// </summary>
         public ICollection<TValue> Values { get { return list.Select(t => t.Value).ToList(); } }
 
+        /// <summary>
+        /// Adds the specified entries to the map.
+        /// </summary>
+        /// <param name="entries">The entries to add to the map.</param>
         public void Add(IDictionary<TKey, TValue> entries)
         {
             Preconditions.CheckNotNull(entries, "entries");
@@ -194,27 +246,51 @@
             }
         }
 
+        /// <summary>
+        /// Returns an enumerator that iterates through the collection.
+        /// </summary>
+        /// <returns>
+        /// An enumerator that can be used to iterate through the collection.
+        /// </returns>
         public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
         {
             return list.GetEnumerator();
         }
 
+        /// <summary>
+        /// Returns an enumerator that iterates through a collection.
+        /// </summary>
+        /// <returns>
+        /// An <see cref="T:System.Collections.IEnumerator" /> object that can be used to iterate through the collection.
+        /// </returns>
         IEnumerator IEnumerable.GetEnumerator()
         {
             return GetEnumerator();
         }
 
+        /// <summary>
+        /// Adds the specified item to the map.
+        /// </summary>
+        /// <param name="item">The item to add to the map.</param>
         void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
         {
             Add(item.Key, item.Value);
         }
 
+        /// <summary>
+        /// Removes all items from the map.
+        /// </summary>
         public void Clear()
         {
             list.Clear();
             map.Clear();
         }
 
+        /// <summary>
+        /// Determines whether map contains an entry equivalent to the given key/value pair.
+        /// </summary>
+        /// <param name="item">The key/value pair to find.</param>
+        /// <returns></returns>
         bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> item)
         {
             TValue value;
@@ -222,11 +298,22 @@
                 && EqualityComparer<TValue>.Default.Equals(item.Value, value);
         }
 
+        /// <summary>
+        /// Copies the key/value pairs in this map to an array.
+        /// </summary>
+        /// <param name="array">The array to copy the entries into.</param>
+        /// <param name="arrayIndex">The index of the array at which to start copying values.</param>
         void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
         {
             list.CopyTo(array, arrayIndex);
         }
 
+        /// <summary>
+        /// Removes the specified key/value pair from the map.
+        /// </summary>
+        /// <remarks>Both the key and the value must be found for the entry to be removed.</remarks>
+        /// <param name="item">The key/value pair to remove.</param>
+        /// <returns><c>true</c> if the key/value pair was found and removed; <c>false</c> otherwise.</returns>
         bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
         {
             if (item.Key == null)
@@ -252,14 +339,34 @@
         /// </summary>
         public bool AllowsNullValues { get { return allowNullValues; } }
 
+        /// <summary>
+        /// Gets the number of elements contained in the map.
+        /// </summary>
         public int Count { get { return list.Count; } }
+
+        /// <summary>
+        /// Gets a value indicating whether the map is read-only.
+        /// </summary>
         public bool IsReadOnly { get { return false; } }
 
+        /// <summary>
+        /// Determines whether the specified <see cref="System.Object" />, is equal to this instance.
+        /// </summary>
+        /// <param name="other">The <see cref="System.Object" /> to compare with this instance.</param>
+        /// <returns>
+        ///   <c>true</c> if the specified <see cref="System.Object" /> is equal to this instance; otherwise, <c>false</c>.
+        /// </returns>
         public override bool Equals(object other)
         {
             return Equals(other as MapField<TKey, TValue>);
         }
 
+        /// <summary>
+        /// Returns a hash code for this instance.
+        /// </summary>
+        /// <returns>
+        /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. 
+        /// </returns>
         public override int GetHashCode()
         {
             var valueComparer = EqualityComparer<TValue>.Default;
@@ -271,6 +378,14 @@
             return hash;
         }
 
+        /// <summary>
+        /// Compares this map with another for equality.
+        /// </summary>
+        /// <remarks>
+        /// The order of the key/value pairs in the maps is not deemed significant in this comparison.
+        /// </remarks>
+        /// <param name="other">The map to compare this with.</param>
+        /// <returns><c>true</c> if <paramref name="other"/> refers to an equal map; <c>false</c> otherwise.</returns>
         public bool Equals(MapField<TKey, TValue> other)
         {
             if (other == null)
@@ -322,6 +437,12 @@
             } while (input.MaybeConsumeTag(codec.MapTag));
         }
 
+        /// <summary>
+        /// Writes the contents of this map to the given coded output stream, using the specified codec
+        /// to encode each entry.
+        /// </summary>
+        /// <param name="output">The output stream to write to.</param>
+        /// <param name="codec">The codec to use for each entry.</param>
         public void WriteTo(CodedOutputStream output, Codec codec)
         {
             var message = new Codec.MessageAdapter(codec);
@@ -334,6 +455,11 @@
             }
         }
 
+        /// <summary>
+        /// Calculates the size of this map based on the given entry codec.
+        /// </summary>
+        /// <param name="codec">The codec to use to encode each entry.</param>
+        /// <returns></returns>
         public int CalculateSize(Codec codec)
         {
             if (Count == 0)
@@ -446,7 +572,7 @@
         }
 
         /// <summary>
-        /// A codec for a specific map field. This contains all the information required to encoded and
+        /// A codec for a specific map field. This contains all the information required to encode and
         /// decode the nested messages.
         /// </summary>
         public sealed class Codec
@@ -455,6 +581,13 @@
             private readonly FieldCodec<TValue> valueCodec;
             private readonly uint mapTag;
 
+            /// <summary>
+            /// Creates a new entry codec based on a separate key codec and value codec,
+            /// and the tag to use for each map entry.
+            /// </summary>
+            /// <param name="keyCodec">The key codec.</param>
+            /// <param name="valueCodec">The value codec.</param>
+            /// <param name="mapTag">The map tag to use to introduce each map entry.</param>
             public Codec(FieldCodec<TKey> keyCodec, FieldCodec<TValue> valueCodec, uint mapTag)
             {
                 this.keyCodec = keyCodec;
diff --git a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
index 3ce19c8..c901864 100644
--- a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
+++ b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
@@ -30,7 +30,6 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 
-using Google.Protobuf.Reflection;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -81,6 +80,11 @@
             return clone;
         }
 
+        /// <summary>
+        /// Adds the entries from the given input stream, decoding them with the specified codec.
+        /// </summary>
+        /// <param name="input">The input stream to read from.</param>
+        /// <param name="codec">The codec to use in order to read each entry.</param>
         public void AddEntriesFrom(CodedInputStream input, FieldCodec<T> codec)
         {
             // TODO: Inline some of the Add code, so we can avoid checking the size on every
@@ -112,6 +116,12 @@
             }
         }
 
+        /// <summary>
+        /// Calculates the size of this collection based on the given codec.
+        /// </summary>
+        /// <param name="codec">The codec to use when encoding each field.</param>
+        /// <returns>The number of bytes that would be written to a <see cref="CodedOutputStream"/> by <see cref="WriteTo"/>,
+        /// using the same codec.</returns>
         public int CalculateSize(FieldCodec<T> codec)
         {
             if (count == 0)
@@ -157,6 +167,12 @@
             }
         }
 
+        /// <summary>
+        /// Writes the contents of this collection to the given <see cref="CodedOutputStream"/>,
+        /// encoding each value using the specified codec.
+        /// </summary>
+        /// <param name="output">The output stream to write to.</param>
+        /// <param name="codec">The codec to use when encoding each value.</param>
         public void WriteTo(CodedOutputStream output, FieldCodec<T> codec)
         {
             if (count == 0)
@@ -200,6 +216,10 @@
             }
         }
 
+        /// <summary>
+        /// Adds the specified item to the collection.
+        /// </summary>
+        /// <param name="item">The item to add.</param>
         public void Add(T item)
         {
             if (item == null)
@@ -210,22 +230,40 @@
             array[count++] = item;
         }
 
+        /// <summary>
+        /// Removes all items from the collection.
+        /// </summary>
         public void Clear()
         {
             array = EmptyArray;
             count = 0;
         }
 
+        /// <summary>
+        /// Determines whether this collection contains the given item.
+        /// </summary>
+        /// <param name="item">The item to find.</param>
+        /// <returns><c>true</c> if this collection contains the given item; <c>false</c> otherwise.</returns>
         public bool Contains(T item)
         {
             return IndexOf(item) != -1;
         }
 
+        /// <summary>
+        /// Copies this collection to the given array.
+        /// </summary>
+        /// <param name="array">The array to copy to.</param>
+        /// <param name="arrayIndex">The first index of the array to copy to.</param>
         public void CopyTo(T[] array, int arrayIndex)
         {
             Array.Copy(this.array, 0, array, arrayIndex, count);
         }
 
+        /// <summary>
+        /// Removes the specified item from the collection
+        /// </summary>
+        /// <param name="item">The item to remove.</param>
+        /// <returns><c>true</c> if the item was found and removed; <c>false</c> otherwise.</returns>
         public bool Remove(T item)
         {
             int index = IndexOf(item);
@@ -239,10 +277,22 @@
             return true;
         }
 
+        /// <summary>
+        /// Gets the number of elements contained in the collection.
+        /// </summary>
         public int Count { get { return count; } }
 
+        /// <summary>
+        /// Gets a value indicating whether the collection is read-only.
+        /// </summary>
         public bool IsReadOnly { get { return false; } }
 
+        // TODO: Remove this overload and just handle it in the one below, at execution time?
+
+        /// <summary>
+        /// Adds all of the specified values into this collection.
+        /// </summary>
+        /// <param name="values">The values to add to this collection.</param>
         public void Add(RepeatedField<T> values)
         {
             if (values == null)
@@ -255,6 +305,10 @@
             count += values.count;
         }
 
+        /// <summary>
+        /// Adds all of the specified values into this collection.
+        /// </summary>
+        /// <param name="values">The values to add to this collection.</param>
         public void Add(IEnumerable<T> values)
         {
             if (values == null)
@@ -268,6 +322,12 @@
             }
         }
 
+        /// <summary>
+        /// Returns an enumerator that iterates through the collection.
+        /// </summary>
+        /// <returns>
+        /// An enumerator that can be used to iterate through the collection.
+        /// </returns>
         public IEnumerator<T> GetEnumerator()
         {
             for (int i = 0; i < count; i++)
@@ -276,16 +336,35 @@
             }
         }
 
+        /// <summary>
+        /// Determines whether the specified <see cref="System.Object" />, is equal to this instance.
+        /// </summary>
+        /// <param name="obj">The <see cref="System.Object" /> to compare with this instance.</param>
+        /// <returns>
+        ///   <c>true</c> if the specified <see cref="System.Object" /> is equal to this instance; otherwise, <c>false</c>.
+        /// </returns>
         public override bool Equals(object obj)
         {
             return Equals(obj as RepeatedField<T>);
         }
 
+        /// <summary>
+        /// Returns an enumerator that iterates through a collection.
+        /// </summary>
+        /// <returns>
+        /// An <see cref="T:System.Collections.IEnumerator" /> object that can be used to iterate through the collection.
+        /// </returns>
         IEnumerator IEnumerable.GetEnumerator()
         {
             return GetEnumerator();
-        }        
+        }
 
+        /// <summary>
+        /// Returns a hash code for this instance.
+        /// </summary>
+        /// <returns>
+        /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. 
+        /// </returns>
         public override int GetHashCode()
         {
             int hash = 0;
@@ -296,6 +375,11 @@
             return hash;
         }
 
+        /// <summary>
+        /// Compares this repeated field with another for equality.
+        /// </summary>
+        /// <param name="other">The repeated field to compare this with.</param>
+        /// <returns><c>true</c> if <paramref name="other"/> refers to an equal repeated field; <c>false</c> otherwise.</returns>
         public bool Equals(RepeatedField<T> other)
         {
             if (ReferenceEquals(other, null))
@@ -322,6 +406,12 @@
             return true;
         }
 
+        /// <summary>
+        /// Returns the index of the given item within the collection, or -1 if the item is not
+        /// present.
+        /// </summary>
+        /// <param name="item">The item to find in the collection.</param>
+        /// <returns>The zero-based index of the item, or -1 if it is not found.</returns>
         public int IndexOf(T item)
         {
             if (item == null)
@@ -340,6 +430,11 @@
             return -1;
         }
 
+        /// <summary>
+        /// Inserts the given item at the specified index.
+        /// </summary>
+        /// <param name="index">The index at which to insert the item.</param>
+        /// <param name="item">The item to insert.</param>
         public void Insert(int index, T item)
         {
             if (item == null)
@@ -356,6 +451,10 @@
             count++;
         }
 
+        /// <summary>
+        /// Removes the item at the given index.
+        /// </summary>
+        /// <param name="index">The zero-based index of the item to remove.</param>
         public void RemoveAt(int index)
         {
             if (index < 0 || index >= count)
@@ -367,6 +466,14 @@
             array[count] = default(T);
         }
 
+        /// <summary>
+        /// Gets or sets the item at the specified index.
+        /// </summary>
+        /// <value>
+        /// The element at the specified index.
+        /// </value>
+        /// <param name="index">The zero-based index of the element to get or set.</param>
+        /// <returns>The item at the specified index.</returns>
         public T this[int index]
         {
             get
diff --git a/csharp/src/Google.Protobuf/FieldCodec.cs b/csharp/src/Google.Protobuf/FieldCodec.cs
index 8546278..1076c2a 100644
--- a/csharp/src/Google.Protobuf/FieldCodec.cs
+++ b/csharp/src/Google.Protobuf/FieldCodec.cs
@@ -41,76 +41,152 @@
     public static class FieldCodec
     {
         // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...)
+
+        /// <summary>
+        /// Retrieves a codec suitable for a string field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<string> ForString(uint tag)
         {
             return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a bytes field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<ByteString> ForBytes(uint tag)
         {
             return new FieldCodec<ByteString>(input => input.ReadBytes(), (output, value) => output.WriteBytes(value), CodedOutputStream.ComputeBytesSize, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a bool field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<bool> ForBool(uint tag)
         {
             return new FieldCodec<bool>(input => input.ReadBool(), (output, value) => output.WriteBool(value), CodedOutputStream.ComputeBoolSize, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an int32 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<int> ForInt32(uint tag)
         {
             return new FieldCodec<int>(input => input.ReadInt32(), (output, value) => output.WriteInt32(value), CodedOutputStream.ComputeInt32Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an sint32 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<int> ForSInt32(uint tag)
         {
             return new FieldCodec<int>(input => input.ReadSInt32(), (output, value) => output.WriteSInt32(value), CodedOutputStream.ComputeSInt32Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a fixed32 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<uint> ForFixed32(uint tag)
         {
             return new FieldCodec<uint>(input => input.ReadFixed32(), (output, value) => output.WriteFixed32(value), 4, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an sfixed32 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<int> ForSFixed32(uint tag)
         {
             return new FieldCodec<int>(input => input.ReadSFixed32(), (output, value) => output.WriteSFixed32(value), 4, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a uint32 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<uint> ForUInt32(uint tag)
         {
             return new FieldCodec<uint>(input => input.ReadUInt32(), (output, value) => output.WriteUInt32(value), CodedOutputStream.ComputeUInt32Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an int64 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<long> ForInt64(uint tag)
         {
             return new FieldCodec<long>(input => input.ReadInt64(), (output, value) => output.WriteInt64(value), CodedOutputStream.ComputeInt64Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an sint64 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<long> ForSInt64(uint tag)
         {
             return new FieldCodec<long>(input => input.ReadSInt64(), (output, value) => output.WriteSInt64(value), CodedOutputStream.ComputeSInt64Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a fixed64 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<ulong> ForFixed64(uint tag)
         {
             return new FieldCodec<ulong>(input => input.ReadFixed64(), (output, value) => output.WriteFixed64(value), 8, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for an sfixed64 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<long> ForSFixed64(uint tag)
         {
             return new FieldCodec<long>(input => input.ReadSFixed64(), (output, value) => output.WriteSFixed64(value), 8, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a uint64 field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<ulong> ForUInt64(uint tag)
         {
             return new FieldCodec<ulong>(input => input.ReadUInt64(), (output, value) => output.WriteUInt64(value), CodedOutputStream.ComputeUInt64Size, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a float field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<float> ForFloat(uint tag)
         {
             return new FieldCodec<float>(input => input.ReadFloat(), (output, value) => output.WriteFloat(value), CodedOutputStream.ComputeFloatSize, tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a double field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<double> ForDouble(uint tag)
         {
             return new FieldCodec<double>(input => input.ReadDouble(), (output, value) => output.WriteDouble(value), CodedOutputStream.ComputeDoubleSize, tag);
@@ -118,6 +194,14 @@
 
         // Enums are tricky. We can probably use expression trees to build these delegates automatically,
         // but it's easy to generate the code for it.
+
+        /// <summary>
+        /// Retrieves a codec suitable for an enum field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <param name="toInt32">A conversion function from <see cref="Int32"/> to the enum type.</param>
+        /// <param name="fromInt32">A conversion function from the enum type to <see cref="Int32"/>.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<T> ForEnum<T>(uint tag, Func<T, int> toInt32, Func<int, T> fromInt32)
         {
             return new FieldCodec<T>(input => fromInt32(
@@ -126,6 +210,12 @@
                 value => CodedOutputStream.ComputeEnumSize(toInt32(value)), tag);
         }
 
+        /// <summary>
+        /// Retrieves a codec suitable for a message field with the given tag.
+        /// </summary>
+        /// <param name="tag">The tag.</param>
+        /// <param name="parser">A parser to use for the message type.</param>
+        /// <returns>A codec for the given tag.</returns>
         public static FieldCodec<T> ForMessage<T>(uint tag, MessageParser<T> parser) where T : IMessage<T>
         {
             return new FieldCodec<T>(input => { T message = parser.CreateTemplate(); input.ReadMessage(message); return message; },
@@ -344,8 +434,20 @@
         /// </summary>
         internal int FixedSize { get { return fixedSize; } }
 
+        /// <summary>
+        /// Gets the tag of the codec.
+        /// </summary>
+        /// <value>
+        /// The tag of the codec.
+        /// </value>
         public uint Tag { get { return tag; } }
 
+        /// <summary>
+        /// Gets the default value of the codec's type.
+        /// </summary>
+        /// <value>
+        /// The default value of the codec's type.
+        /// </value>
         public T DefaultValue { get { return defaultValue; } }
 
         /// <summary>
@@ -360,6 +462,11 @@
             }
         }
 
+        /// <summary>
+        /// Reads a value of the codec type from the given <see cref="CodedInputStream"/>.
+        /// </summary>
+        /// <param name="input">The input stream to read from.</param>
+        /// <returns>The value read from the stream.</returns>
         public T Read(CodedInputStream input)
         {
             return reader(input);
diff --git a/csharp/src/Google.Protobuf/Google.Protobuf.csproj b/csharp/src/Google.Protobuf/Google.Protobuf.csproj
index 8a19067..033edfb 100644
--- a/csharp/src/Google.Protobuf/Google.Protobuf.csproj
+++ b/csharp/src/Google.Protobuf/Google.Protobuf.csproj
@@ -24,12 +24,14 @@
     <OutputPath>bin\Debug</OutputPath>
     <IntermediateOutputPath>obj\Debug\</IntermediateOutputPath>
     <DocumentationFile>bin\Debug\Google.Protobuf.xml</DocumentationFile>
-    <NoWarn>1591, 1570, 1571, 1572, 1573, 1574</NoWarn>
+    <NoWarn>
+    </NoWarn>
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>
     <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -37,12 +39,14 @@
     <OutputPath>bin\Release</OutputPath>
     <IntermediateOutputPath>obj\Release\</IntermediateOutputPath>
     <DocumentationFile>$(OutputPath)\$(AssemblyName).xml</DocumentationFile>
-    <NoWarn>1591, 1570, 1571, 1572, 1573, 1574</NoWarn>
+    <NoWarn>
+    </NoWarn>
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>
     <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -50,7 +54,8 @@
     <OutputPath>bin\ReleaseSigned</OutputPath>
     <IntermediateOutputPath>obj\ReleaseSigned\</IntermediateOutputPath>
     <DocumentationFile>$(OutputPath)\$(AssemblyName).xml</DocumentationFile>
-    <NoWarn>1591, 1570, 1571, 1572, 1573, 1574</NoWarn>
+    <NoWarn>
+    </NoWarn>
     <DefineConstants>TRACE;SIGNED</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
@@ -58,6 +63,7 @@
     <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
     <SignAssembly>True</SignAssembly>
     <AssemblyOriginatorKeyFile>C:\keys\Google.Protobuf.snk</AssemblyOriginatorKeyFile>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="mscorlib" />
diff --git a/csharp/src/Google.Protobuf/IMessage.cs b/csharp/src/Google.Protobuf/IMessage.cs
index 60c6f8c..147c83c 100644
--- a/csharp/src/Google.Protobuf/IMessage.cs
+++ b/csharp/src/Google.Protobuf/IMessage.cs
@@ -91,8 +91,9 @@
 
     /// <summary>
     /// Generic interface for a deeply cloneable type.
-    /// <summary>
+    /// </summary>
     /// <remarks>
+    /// <para>
     /// All generated messages implement this interface, but so do some non-message types.
     /// Additionally, due to the type constraint on <c>T</c> in <see cref="IMessage{T}"/>,
     /// it is simpler to keep this as a separate interface.
diff --git a/csharp/src/Google.Protobuf/InvalidProtocolBufferException.cs b/csharp/src/Google.Protobuf/InvalidProtocolBufferException.cs
index 4f89347..bbba9b3 100644
--- a/csharp/src/Google.Protobuf/InvalidProtocolBufferException.cs
+++ b/csharp/src/Google.Protobuf/InvalidProtocolBufferException.cs
@@ -45,7 +45,7 @@
         {
         }
 
-        public static InvalidProtocolBufferException TruncatedMessage()
+        internal static InvalidProtocolBufferException TruncatedMessage()
         {
             return new InvalidProtocolBufferException(
                 "While parsing a protocol message, the input ended unexpectedly " +
@@ -61,12 +61,15 @@
                 "which claimed to have negative size.");
         }
 
-        public static InvalidProtocolBufferException MalformedVarint()
+        internal static InvalidProtocolBufferException MalformedVarint()
         {
             return new InvalidProtocolBufferException(
                 "CodedInputStream encountered a malformed varint.");
         }
 
+        /// <summary>
+        /// Creates an exception for an error condition of an invalid tag being encountered.
+        /// </summary>
         public static InvalidProtocolBufferException InvalidTag()
         {
             return new InvalidProtocolBufferException(
diff --git a/csharp/src/Google.Protobuf/JsonFormatter.cs b/csharp/src/Google.Protobuf/JsonFormatter.cs
index 999e106..edc4718 100644
--- a/csharp/src/Google.Protobuf/JsonFormatter.cs
+++ b/csharp/src/Google.Protobuf/JsonFormatter.cs
@@ -114,11 +114,20 @@
 
         private readonly Settings settings;
 
+        /// <summary>
+        /// Creates a new formatted with the given settings.
+        /// </summary>
+        /// <param name="settings">The settings.</param>
         public JsonFormatter(Settings settings)
         {
             this.settings = settings;
         }
 
+        /// <summary>
+        /// Formats the specified message as JSON.
+        /// </summary>
+        /// <param name="message">The message to format.</param>
+        /// <returns>The formatted message.</returns>
         public string Format(IMessage message)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -768,6 +777,10 @@
             /// </summary>
             public bool FormatDefaultValues { get { return formatDefaultValues; } }
 
+            /// <summary>
+            /// Creates a new <see cref="Settings"/> object with the specified formatting of default values.
+            /// </summary>
+            /// <param name="formatDefaultValues"><c>true</c> if default values (0, empty strings etc) should be formatted; <c>false</c> otherwise.</param>
             public Settings(bool formatDefaultValues)
             {
                 this.formatDefaultValues = formatDefaultValues;
diff --git a/csharp/src/Google.Protobuf/MessageExtensions.cs b/csharp/src/Google.Protobuf/MessageExtensions.cs
index 6e7d47b..ee78dc8 100644
--- a/csharp/src/Google.Protobuf/MessageExtensions.cs
+++ b/csharp/src/Google.Protobuf/MessageExtensions.cs
@@ -39,6 +39,11 @@
     /// </summary>
     public static class MessageExtensions
     {
+        /// <summary>
+        /// Merges data from the given byte array into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="data">The data to merge, which must be protobuf-encoded binary data.</param>
         public static void MergeFrom(this IMessage message, byte[] data)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -48,6 +53,11 @@
             input.CheckLastTagWas(0);
         }
 
+        /// <summary>
+        /// Merges data from the given byte string into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="data">The data to merge, which must be protobuf-encoded binary data.</param>
         public static void MergeFrom(this IMessage message, ByteString data)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -57,6 +67,11 @@
             input.CheckLastTagWas(0);
         }
 
+        /// <summary>
+        /// Merges data from the given stream into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="input">Stream containing the data to merge, which must be protobuf-encoded binary data.</param>
         public static void MergeFrom(this IMessage message, Stream input)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -66,6 +81,15 @@
             codedInput.CheckLastTagWas(0);
         }
 
+        /// <summary>
+        /// Merges length-delimited data from the given stream into an existing message.
+        /// </summary>
+        /// <remarks>
+        /// The stream is expected to contain a length and then the data. Only the amount of data
+        /// specified by the length will be consumed.
+        /// </remarks>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="input">Stream containing the data to merge, which must be protobuf-encoded binary data.</param>
         public static void MergeDelimitedFrom(this IMessage message, Stream input)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -75,6 +99,11 @@
             message.MergeFrom(limitedStream);
         }
 
+        /// <summary>
+        /// Converts the given message into a byte array in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to convert.</param>
+        /// <returns>The message data as a byte array.</returns>
         public static byte[] ToByteArray(this IMessage message)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -85,6 +114,11 @@
             return result;
         }
 
+        /// <summary>
+        /// Writes the given message data to the given stream in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to write to the stream.</param>
+        /// <param name="output">The stream to write to.</param>
         public static void WriteTo(this IMessage message, Stream output)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -94,6 +128,11 @@
             codedOutput.Flush();
         }
 
+        /// <summary>
+        /// Writes the length and then data of the given message to a stream.
+        /// </summary>
+        /// <param name="message">The message to write.</param>
+        /// <param name="output">The output stream to write to.</param>
         public static void WriteDelimitedTo(this IMessage message, Stream output)
         {
             Preconditions.CheckNotNull(message, "message");
@@ -104,6 +143,11 @@
             codedOutput.Flush();
         }
 
+        /// <summary>
+        /// Converts the given message into a byte string in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to convert.</param>
+        /// <returns>The message data as a byte string.</returns>
         public static ByteString ToByteString(this IMessage message)
         {
             Preconditions.CheckNotNull(message, "message");
diff --git a/csharp/src/Google.Protobuf/MessageParser.cs b/csharp/src/Google.Protobuf/MessageParser.cs
index bfa63ae..6a6f101 100644
--- a/csharp/src/Google.Protobuf/MessageParser.cs
+++ b/csharp/src/Google.Protobuf/MessageParser.cs
@@ -90,6 +90,11 @@
             return message;
         }
 
+        /// <summary>
+        /// Parses a message from the given byte string.
+        /// </summary>
+        /// <param name="data">The data to parse.</param>
+        /// <returns>The parsed message.</returns>
         public T ParseFrom(ByteString data)
         {
             Preconditions.CheckNotNull(data, "data");
@@ -98,6 +103,11 @@
             return message;
         }
 
+        /// <summary>
+        /// Parses a message from the given stream.
+        /// </summary>
+        /// <param name="input">The stream to parse.</param>
+        /// <returns>The parsed message.</returns>
         public T ParseFrom(Stream input)
         {
             T message = factory();
@@ -105,6 +115,15 @@
             return message;
         }
 
+        /// <summary>
+        /// Parses a length-delimited message from the given stream.
+        /// </summary>
+        /// <remarks>
+        /// The stream is expected to contain a length and then the data. Only the amount of data
+        /// specified by the length will be consumed.
+        /// </remarks>
+        /// <param name="input">The stream to parse.</param>
+        /// <returns>The parsed message.</returns>
         public T ParseDelimitedFrom(Stream input)
         {
             T message = factory();
@@ -112,6 +131,11 @@
             return message;
         }
 
+        /// <summary>
+        /// Parses a message from the given coded input stream.
+        /// </summary>
+        /// <param name="input">The stream to parse.</param>
+        /// <returns>The parsed message.</returns>
         public T ParseFrom(CodedInputStream input)
         {
             T message = factory();
diff --git a/csharp/src/Google.Protobuf/Reflection/DescriptorBase.cs b/csharp/src/Google.Protobuf/Reflection/DescriptorBase.cs
index 0300cd5..194041a 100644
--- a/csharp/src/Google.Protobuf/Reflection/DescriptorBase.cs
+++ b/csharp/src/Google.Protobuf/Reflection/DescriptorBase.cs
@@ -61,6 +61,9 @@
             get { return index; }
         }
 
+        /// <summary>
+        /// Returns the name of the entity (field, message etc) being described.
+        /// </summary>
         public abstract string Name { get; }
 
         /// <summary>
diff --git a/csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs
index 29833c4..b212ce9 100644
--- a/csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs
@@ -51,11 +51,20 @@
         }
 
         internal EnumValueDescriptorProto Proto { get { return proto; } }
-        
+
+        /// <summary>
+        /// Returns the name of the enum value described by this object.
+        /// </summary>
         public override string Name { get { return proto.Name; } }
 
+        /// <summary>
+        /// Returns the number associated with this enum value.
+        /// </summary>
         public int Number { get { return Proto.Number; } }
 
+        /// <summary>
+        /// Returns the enum descriptor that this value is part of.
+        /// </summary>
         public EnumDescriptor EnumDescriptor { get { return enumDescriptor; } }
     }
 }
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
index 60f2bb8..bb8e9bb 100644
--- a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
@@ -93,6 +93,15 @@
 
         internal FieldDescriptorProto Proto { get { return proto; } }
 
+        /// <summary>
+        /// Returns the accessor for this field, or <c>null</c> if this descriptor does
+        /// not support reflective access.
+        /// </summary>
+        /// <remarks>
+        /// While a <see cref="FieldDescriptor"/> describes the field, it does not provide
+        /// any way of obtaining or changing the value of the field within a specific message;
+        /// that is the responsibility of the accessor.
+        /// </remarks>
         public IFieldAccessor Accessor { get { return accessor; } }
         
         /// <summary>
@@ -141,43 +150,61 @@
                 default:
                     throw new ArgumentException("Invalid type specified");
             }
-        }        
+        }
 
+        /// <summary>
+        /// Returns <c>true</c> if this field is a repeated field; <c>false</c> otherwise.
+        /// </summary>
         public bool IsRepeated
         {
             get { return Proto.Label == FieldDescriptorProto.Types.Label.LABEL_REPEATED; }
         }
 
+        /// <summary>
+        /// Returns <c>true</c> if this field is a map field; <c>false</c> otherwise.
+        /// </summary>
         public bool IsMap
         {
             get { return fieldType == FieldType.Message && messageType.Proto.Options != null && messageType.Proto.Options.MapEntry; }
         }
 
+        // TODO(jonskeet): Check whether this is correct with proto3, where we default to packed...
+
+        /// <summary>
+        /// Returns <c>true</c> if this field is a packed, repeated field; <c>false</c> otherwise.
+        /// </summary>
         public bool IsPacked
         {
             get { return Proto.Options != null && Proto.Options.Packed; }
         }        
 
         /// <summary>
-        /// Get the field's containing type. For extensions, this is the type being
-        /// extended, not the location where the extension was defined. See
-        /// <see cref="ExtensionScope" />.
+        /// Get the field's containing message type.
         /// </summary>
         public MessageDescriptor ContainingType
         {
             get { return containingType; }
         }
 
+        /// <summary>
+        /// Returns the oneof containing this field, or <c>null</c> if it is not part of a oneof.
+        /// </summary>
         public OneofDescriptor ContainingOneof
         {
             get { return containingOneof; }
-        }        
+        }
 
+        /// <summary>
+        /// Returns  the type of the field.
+        /// </summary>
         public FieldType FieldType
         {
             get { return fieldType; }
         }
 
+        /// <summary>
+        /// Returns the field number declared in the proto file.
+        /// </summary>
         public int FieldNumber
         {
             get { return Proto.Number; }
diff --git a/csharp/src/Google.Protobuf/Reflection/FieldType.cs b/csharp/src/Google.Protobuf/Reflection/FieldType.cs
index 41fa702..1658e34 100644
--- a/csharp/src/Google.Protobuf/Reflection/FieldType.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FieldType.cs
@@ -33,28 +33,81 @@
 namespace Google.Protobuf.Reflection
 {
     /// <summary>
-    /// Enumeration of all the possible field types. The odd formatting is to make it very clear
-    /// which attribute applies to which value, while maintaining a compact format.
+    /// Enumeration of all the possible field types.
     /// </summary>
     public enum FieldType
     {
+        /// <summary>
+        /// The <c>double</c> field type.
+        /// </summary>
         Double,
+        /// <summary>
+        /// The <c>float</c> field type.
+        /// </summary>
         Float,
+        /// <summary>
+        /// The <c>int64</c> field type.
+        /// </summary>
         Int64,
+        /// <summary>
+        /// The <c>uint64</c> field type.
+        /// </summary>
         UInt64,
+        /// <summary>
+        /// The <c>int32</c> field type.
+        /// </summary>
         Int32,
+        /// <summary>
+        /// The <c>fixed64</c> field type.
+        /// </summary>
         Fixed64,
+        /// <summary>
+        /// The <c>fixed32</c> field type.
+        /// </summary>
         Fixed32,
+        /// <summary>
+        /// The <c>bool</c> field type.
+        /// </summary>
         Bool,
+        /// <summary>
+        /// The <c>string</c> field type.
+        /// </summary>
         String,
+        /// <summary>
+        /// The field type used for groups (not supported in this implementation).
+        /// </summary>
         Group,
+        /// <summary>
+        /// The field type used for message fields.
+        /// </summary>
         Message,
+        /// <summary>
+        /// The <c>bytes</c> field type.
+        /// </summary>
         Bytes,
+        /// <summary>
+        /// The <c>uint32</c> field type.
+        /// </summary>
         UInt32,
+        /// <summary>
+        /// The <c>sfixed32</c> field type.
+        /// </summary>
         SFixed32,
+        /// <summary>
+        /// The <c>sfixed64</c> field type.
+        /// </summary>
         SFixed64,
+        /// <summary>
+        /// The <c>sint32</c> field type.
+        /// </summary>
         SInt32,
+        /// <summary>
+        /// The <c>sint64</c> field type.
+        /// </summary>
         SInt64,
+        /// <summary>
+        /// The field type used for enum fields.
+        /// </summary>
         Enum
     }
 }
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
index c17c4cc..7292770 100644
--- a/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
@@ -51,18 +51,7 @@
         private readonly IList<FileDescriptor> dependencies;
         private readonly IList<FileDescriptor> publicDependencies;
         private readonly DescriptorPool pool;
-
-        public enum ProtoSyntax
-        {
-            Proto2,
-            Proto3
-        }
-
-        public ProtoSyntax Syntax
-        {
-            get { return proto.Syntax == "proto3" ? ProtoSyntax.Proto3 : ProtoSyntax.Proto2; }
-        }
-
+        
         private FileDescriptor(ByteString descriptorData, FileDescriptorProto proto, FileDescriptor[] dependencies, DescriptorPool pool, bool allowUnknownDependencies, GeneratedCodeInfo generatedCodeInfo)
         {
             this.descriptorData = descriptorData;
@@ -368,7 +357,13 @@
                 throw new ArgumentException("Invalid embedded descriptor for \"" + proto.Name + "\".", e);
             }
         }
-        
+
+        /// <summary>
+        /// Returns a <see cref="System.String" /> that represents this instance.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="System.String" /> that represents this instance.
+        /// </returns>
         public override string ToString()
         {
             return "FileDescriptor for " + proto.Name;
diff --git a/csharp/src/Google.Protobuf/Reflection/IDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/IDescriptor.cs
index 6506db1..318d58c 100644
--- a/csharp/src/Google.Protobuf/Reflection/IDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/IDescriptor.cs
@@ -37,8 +37,19 @@
     /// </summary>
     public interface IDescriptor
     {
+        /// <summary>
+        /// Returns the name of the entity (message, field etc) being described.
+        /// </summary>
         string Name { get; }
+
+        /// <summary>
+        /// Returns the fully-qualified name of the entity being described.
+        /// </summary>
         string FullName { get; }
+
+        /// <summary>
+        /// Returns the descriptor for the .proto file that this entity is part of.
+        /// </summary>
         FileDescriptor File { get; }
     }    
 }
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/Reflection/IFieldAccessor.cs b/csharp/src/Google.Protobuf/Reflection/IFieldAccessor.cs
index 3f4f05f..f97d73e 100644
--- a/csharp/src/Google.Protobuf/Reflection/IFieldAccessor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/IFieldAccessor.cs
@@ -30,6 +30,9 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 
+using System;
+using System.Collections;
+
 namespace Google.Protobuf.Reflection
 {
     /// <summary>
@@ -64,7 +67,7 @@
         /// Repeated fields are mutated by fetching the value and manipulating it as a list.
         /// Map fields are mutated by fetching the value and manipulating it as a dictionary.
         /// </remarks>
-        /// <exception cref="InvalidOperationException">The field is not a "simple" field, or the message is frozen.</exception>
+        /// <exception cref="InvalidOperationException">The field is not a "simple" field.</exception>
         void SetValue(object message, object value);
     }
 }
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
index 0b562de..82901f1 100644
--- a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
@@ -30,7 +30,6 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 
-using Google.Protobuf.Collections;
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
@@ -163,6 +162,9 @@
             get { return enumTypes; }
         }
 
+        /// <value>
+        /// An unmodifiable list of the "oneof" field collections in this message type.
+        /// </value>
         public IList<OneofDescriptor> Oneofs
         {
             get { return oneofs; }
@@ -276,7 +278,7 @@
             /// <summary>
             /// Retrieves the descriptor for the field with the given name.
             /// </summary>
-            /// <param name="number">Number of the field to retrieve the descriptor for</param>
+            /// <param name="name">Name of the field to retrieve the descriptor for</param>
             /// <returns>The descriptor for the given field</returns>
             /// <exception cref="KeyNotFoundException">The message descriptor does not contain a field
             /// with the given name</exception>
diff --git a/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs b/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs
index 8631a1c..ff51291 100644
--- a/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs
@@ -58,6 +58,12 @@
             clearDelegate = ReflectionUtil.CreateActionObject(clearMethod);
         }
 
+        /// <summary>
+        /// Gets the descriptor for this oneof.
+        /// </summary>
+        /// <value>
+        /// The descriptor of the oneof.
+        /// </value>
         public OneofDescriptor Descriptor { get { return descriptor; } }
 
         /// <summary>
diff --git a/csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs
index 8571a5e..d51ee52 100644
--- a/csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs
@@ -32,11 +32,14 @@
 
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Google.Protobuf.Compatibility;
 
 namespace Google.Protobuf.Reflection
 {
+    /// <summary>
+    /// Describes a "oneof" field collection in a message type: a set of
+    /// fields of which at most one can be set in any particular message.
+    /// </summary>
     public sealed class OneofDescriptor : DescriptorBase
     {
         private readonly OneofDescriptorProto proto;
@@ -59,13 +62,33 @@
         /// </summary>
         public override string Name { get { return proto.Name; } }
 
+        /// <summary>
+        /// Gets the message type containing this oneof.
+        /// </summary>
+        /// <value>
+        /// The message type containing this oneof.
+        /// </value>
         public MessageDescriptor ContainingType
         {
             get { return containingType; }
         }
 
+        /// <summary>
+        /// Gets the fields within this oneof, in declaration order.
+        /// </summary>
+        /// <value>
+        /// The fields within this oneof, in declaration order.
+        /// </value>
         public IList<FieldDescriptor> Fields { get { return fields; } }
 
+        /// <summary>
+        /// Gets an accessor for reflective access to the values associated with the oneof
+        /// in a particular message.
+        /// </summary>
+        /// <value>
+        /// The accessor used for reflective access, or <c>null</c> if reflection is not
+        /// supported by this descriptor.
+        /// </value>
         public OneofAccessor Accessor { get { return accessor; } }
 
         internal void CrossLink()
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/DurationPartial.cs b/csharp/src/Google.Protobuf/WellKnownTypes/DurationPartial.cs
index c69d1b2..18ebefd 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/DurationPartial.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/DurationPartial.cs
@@ -38,7 +38,13 @@
     // providing a conversion to TimeSpan and convenience operators.
     public partial class Duration
     {
+        /// <summary>
+        /// The number of nanoseconds in a second.
+        /// </summary>
         public const int NanosecondsPerSecond = 1000000000;
+        /// <summary>
+        /// The number of nanoseconds in a BCL tick (as used by <see cref="TimeSpan"/> and <see cref="DateTime"/>).
+        /// </summary>
         public const int NanosecondsPerTick = 100;
 
         /// <summary>
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs b/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
index a3806b5..dd485d3 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
@@ -43,16 +43,35 @@
     /// </summary>
     public static class TimeExtensions
     {
+        /// <summary>
+        /// Converts the given <see cref="DateTime"/> to a <see cref="Timestamp"/>.
+        /// </summary>
+        /// <param name="dateTime">The date and time to convert to a timestamp.</param>
+        /// <exception cref="ArgumentException">The <paramref name="dateTime"/> value has a <see cref="DateTime.Kind"/>other than <c>Utc</c>.</exception>
+        /// <returns>The converted timestamp.</returns>
         public static Timestamp ToTimestamp(this DateTime dateTime)
         {
             return Timestamp.FromDateTime(dateTime);
         }
 
+        /// <summary>
+        /// Converts the given <see cref="DateTimeOffset"/> to a <see cref="Timestamp"/>
+        /// </summary>
+        /// <remarks>The offset is taken into consideration when converting the value (so the same instant in time
+        /// is represented) but is not a separate part of the resulting value. In other words, there is no
+        /// roundtrip operation to retrieve the original <c>DateTimeOffset</c>.</remarks>
+        /// <param name="dateTimeOffset">The date and time (with UTC offset) to convert to a timestamp.</param>
+        /// <returns>The converted timestamp.</returns>
         public static Timestamp ToTimestamp(this DateTimeOffset dateTimeOffset)
         {
             return Timestamp.FromDateTimeOffset(dateTimeOffset);
         }
 
+        /// <summary>
+        /// Converts the given <see cref="TimeSpan"/> to a <see cref="Duration"/>.
+        /// </summary>
+        /// <param name="timeSpan">The time span to convert.</param>
+        /// <returns>The converted duration.</returns>
         public static Duration ToDuration(this TimeSpan timeSpan)
         {
             return Duration.FromTimeSpan(timeSpan);
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/TimestampPartial.cs b/csharp/src/Google.Protobuf/WellKnownTypes/TimestampPartial.cs
index 1aa392c..6858435 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/TimestampPartial.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/TimestampPartial.cs
@@ -136,9 +136,12 @@
         }
 
         /// <summary>
-        /// Converts the specified <see cref="DateTimeOffset"/> to a <see cref="Timestamp"/>.
+        /// Converts the given <see cref="DateTimeOffset"/> to a <see cref="Timestamp"/>
         /// </summary>
-        /// <param name="dateTime"></param>
+        /// <remarks>The offset is taken into consideration when converting the value (so the same instant in time
+        /// is represented) but is not a separate part of the resulting value. In other words, there is no
+        /// roundtrip operation to retrieve the original <c>DateTimeOffset</c>.</remarks>
+        /// <param name="dateTimeOffset">The date and time (with UTC offset) to convert to a timestamp.</param>
         /// <returns>The converted timestamp.</returns>
         public static Timestamp FromDateTimeOffset(DateTimeOffset dateTimeOffset)
         {
diff --git a/csharp/src/Google.Protobuf/WireFormat.cs b/csharp/src/Google.Protobuf/WireFormat.cs
index c1712da..bbd7e4f 100644
--- a/csharp/src/Google.Protobuf/WireFormat.cs
+++ b/csharp/src/Google.Protobuf/WireFormat.cs
@@ -30,9 +30,6 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 
-using System;
-using Google.Protobuf.Reflection;
-
 namespace Google.Protobuf
 {
     /// <summary>
@@ -59,13 +56,34 @@
 
         #endregion
 
+        /// <summary>
+        /// Wire types within protobuf encoding.
+        /// </summary>
         public enum WireType : uint
         {
+            /// <summary>
+            /// Variable-length integer.
+            /// </summary>
             Varint = 0,
+            /// <summary>
+            /// A fixed-length 64-bit value.
+            /// </summary>
             Fixed64 = 1,
+            /// <summary>
+            /// A length-delimited value, i.e. a length followed by that many bytes of data.
+            /// </summary>
             LengthDelimited = 2,
+            /// <summary>
+            /// A "start group" value - not supported by this implementation.
+            /// </summary>
             StartGroup = 3,
+            /// <summary>
+            /// An "end group" value - not supported by this implementation.
+            /// </summary>
             EndGroup = 4,
+            /// <summary>
+            /// A fixed-length 32-bit value.
+            /// </summary>
             Fixed32 = 5
         }
         
@@ -80,6 +98,11 @@
             return (WireType) (tag & TagTypeMask);
         }
 
+        /// <summary>
+        /// Determines whether the given tag is an end group tag.
+        /// </summary>
+        /// <param name="tag">The tag to check.</param>
+        /// <returns><c>true</c> if the given tag is an end group tag; <c>false</c> otherwise.</returns>
         public static bool IsEndGroupTag(uint tag)
         {
             return (WireType) (tag & TagTypeMask) == WireType.EndGroup;
@@ -99,64 +122,6 @@
         public static uint MakeTag(int fieldNumber, WireType wireType)
         {
             return (uint) (fieldNumber << TagTypeBits) | (uint) wireType;
-        }
-
-        public static uint MakeTag(FieldDescriptor field)
-        {
-            return MakeTag(field.FieldNumber, GetWireType(field));
-        }
-
-        /// <summary>
-        /// Returns the wire type for the given field descriptor. This differs
-        /// from GetWireType(FieldType) for packed repeated fields.
-        /// </summary>
-        internal static WireType GetWireType(FieldDescriptor descriptor)
-        {
-            return descriptor.IsPacked ? WireType.LengthDelimited : GetWireType(descriptor.FieldType);
-        }
-
-        /// <summary>
-        /// Converts a field type to its wire type. Done with a switch for the sake
-        /// of speed - this is significantly faster than a dictionary lookup.
-        /// </summary>
-        public static WireType GetWireType(FieldType fieldType)
-        {
-            switch (fieldType)
-            {
-                case FieldType.Double:
-                    return WireType.Fixed64;
-                case FieldType.Float:
-                    return WireType.Fixed32;
-                case FieldType.Int64:
-                case FieldType.UInt64:
-                case FieldType.Int32:
-                    return WireType.Varint;
-                case FieldType.Fixed64:
-                    return WireType.Fixed64;
-                case FieldType.Fixed32:
-                    return WireType.Fixed32;
-                case FieldType.Bool:
-                    return WireType.Varint;
-                case FieldType.String:
-                    return WireType.LengthDelimited;
-                case FieldType.Group:
-                    return WireType.StartGroup;
-                case FieldType.Message:
-                case FieldType.Bytes:
-                    return WireType.LengthDelimited;
-                case FieldType.UInt32:
-                    return WireType.Varint;
-                case FieldType.SFixed32:
-                    return WireType.Fixed32;
-                case FieldType.SFixed64:
-                    return WireType.Fixed64;
-                case FieldType.SInt32:
-                case FieldType.SInt64:
-                case FieldType.Enum:
-                    return WireType.Varint;
-                default:
-                    throw new ArgumentOutOfRangeException("fieldType", "No such field type");
-            }
-        }
+        }        
     }
 }
\ No newline at end of file