Go To The Source Luke

The standard answer to the people wanting to really understand how .NET works is to go to the source, i.e. the Rotor source code. Now, there is one step better: these great presentations from the Rotor Conference (scroll to the bottom) from people like Peter, and Jason amongst others. Want to undertand the JIT? The GC? Its all here! via
[Sam Gentile’s Blog]

Another great resource is the hyperlinked version of the C# Language Specification.