I have been a C++ programmer for last several years with a bit of C# here and there. In my latest job, I work heavily on C#. I picked most of my C# by following the code-base or random google searches on what I wanted to do at that point (like threading in C#).

I feel a time has come to invest some time into understanding the language internals and also understanding the .NET framework from an architectural point of view.

Can someone recommend the "gold standard" text/resource for accomplishing these? What about that resource makes it the best? What were your experiences with it?