sdether
diff --git a/‎MongoDB.Net-Tests/Bson/TestRoundTrips.cs
Copy file name to clipboardExpand all lines: MongoDB.Net-Tests/Bson/TestRoundTrips.cs
+28-1 b/‎MongoDB.Net-Tests/Bson/TestRoundTrips.cs
Copy file name to clipboardExpand all lines: MongoDB.Net-Tests/Bson/TestRoundTrips.cs
+28-1
diff --git a/‎MongoDBDriver/Binary.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Binary.cs
+3-5 b/‎MongoDBDriver/Binary.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Binary.cs
+3-5
diff --git a/‎MongoDBDriver/Bson/BsonReader.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Bson/BsonReader.cs
+9-1 b/‎MongoDBDriver/Bson/BsonReader.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Bson/BsonReader.cs
+9-1
diff --git a/‎MongoDBDriver/Bson/BsonWriter.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Bson/BsonWriter.cs
+30-16 b/‎MongoDBDriver/Bson/BsonWriter.cs
Copy file name to clipboardExpand all lines: MongoDBDriver/Bson/BsonWriter.cs
+30-16
@@ -79,6 +79,33 @@ public void TestDateUTC(){
 
             Assert.AreEqual(now.Hour,then.Hour, "Date did not round trip right.");
 
-        }        
+        }
+
+        [Test]
+        public void TestGUID()
+        {
+            MemoryStream ms = new MemoryStream();
+            BsonWriter writer = new BsonWriter(ms);
+
+            Guid guid = Guid.NewGuid();
+
+            Document source = new Document();
+            source.Append("uuid", guid);
+
+            /*Binary b = new Binary(guid.ToByteArray());
+            b.Subtype = Binary.TypeCode.Uuid;
+            source.Append("uuid", b);*/
+
+            writer.Write(source);
+            writer.Flush();
+            ms.Seek(0, SeekOrigin.Begin);
+
+            BsonReader reader = new BsonReader(ms);
+            Document copy = reader.Read();
+
+            Guid read = (Guid)copy["uuid"];
+
+            Assert.AreEqual(guid, read, "UUID did not round trip right.");
+        }
     }
 }
@@ -8,11 +8,9 @@ public class Binary{
 		public enum TypeCode:byte{
 			Unknown = 0,
 			General = 2,
-
-            // Uuid is now replaced by Binary
-			//Uuid = 3,
-			
-            Md5 = 5,
+			// Uuid is now replaced by Guid
+            //Uuid = 3,
+			Md5 = 5,
 			UserDefined = 80
 		}
 
 
@@ -148,7 +148,15 @@ public Object ReadElementType (sbyte typeNum){
                 }
                 byte[] bytes = reader.ReadBytes (size);
                 position += size;
-                Binary b = new Binary ();
+
+                // From http://en.wikipedia.org/wiki/Universally_Unique_Identifier
+                // The most widespread use of this standard is in Microsoft's Globally Unique Identifiers (GUIDs).
+                if (subtype == 3 && 16 == size)
+                {
+                    return new Guid(bytes);
+                }
+
+                Binary b = new Binary();
                 b.Bytes = bytes;
                 b.Subtype = (Binary.TypeCode)subtype;
                 return b;
 
@@ -117,16 +117,22 @@ public void WriteValue(BsonDataType dt, Object obj){
                     return;
                 }
                 case BsonDataType.Binary:{
-                    Binary b = (Binary)obj;
-                    if(b.Subtype == Binary.TypeCode.General){
-                        writer.Write(b.Bytes.Length + 4);
-                        writer.Write((byte)b.Subtype);
-                        writer.Write(b.Bytes.Length);
-                    }else{
-                        writer.Write(b.Bytes.Length);
-                        writer.Write((byte)b.Subtype);
+                    if (obj is Guid) {
+                        writer.Write((int)16);
+                        writer.Write((byte)3);
+                        writer.Write(((Guid)obj).ToByteArray());
+                    } else {
+                        Binary b = (Binary)obj;
+                        if(b.Subtype == Binary.TypeCode.General){
+                            writer.Write(b.Bytes.Length + 4);
+                            writer.Write((byte)b.Subtype);
+                            writer.Write(b.Bytes.Length);
+                        }else{
+                            writer.Write(b.Bytes.Length);
+                            writer.Write((byte)b.Subtype);
+                        }
+                        writer.Write(b.Bytes);
                     }
-                    writer.Write(b.Bytes);                    
                     return;
                 }
                 default:
@@ -202,14 +208,20 @@ public int CalculateSize(Object val){
                     return size;
                     }
                 case BsonDataType.Binary:{
-                    Binary b = (Binary)val;
-                    int size = 4; //size int
-                    size += 1; //subtype
-                    if(b.Subtype == Binary.TypeCode.General){
-                        size += 4; //embedded size int
+                    if (val is Guid)
+                        return 21;
+                    else
+                    {
+                        Binary b = (Binary)val;
+                        int size = 4; //size int
+                        size += 1; //subtype
+                        if (b.Subtype == Binary.TypeCode.General)
+                        {
+                            size += 4; //embedded size int
+                        }
+                        size += b.Bytes.Length;
+                        return size;
                     }
-                    size += b.Bytes.Length;
-                    return size;
                 }
                 default:
                     throw new NotImplementedException(String.Format("Calculating size of {0} is not implemented.",val.GetType().Name));
@@ -295,6 +307,8 @@ protected BsonDataType TranslateToBsonType(Object val){
                 ret = BsonDataType.Null;
             }else if(t == typeof(Binary)){
                 ret = BsonDataType.Binary;
+            }else if(t == typeof(Guid)){
+                ret = BsonDataType.Binary;
             }else if(t == typeof(MongoMinKey)){
                 ret = BsonDataType.MinKey;
             }else if(t == typeof(MongoMaxKey)){