I'm using .NET 3.5. I think I know the answer to this, but am looking for confirmation so should be a quick one! There doesn't appear to be a generic implementation of OrderedDictionary (which is in System.Collections.Specialized namespace). Is there one that I'm missing? I've found implementations out there to provide the functionality, but wondered if/why there isn't a generic implementation out-of-the-box and if anyone knows whether it's something in .NET 4.0?