User152549106 posted
If you're looking for a book that was checked on the final release candidate, not some early beta, I'd suggest starting with:
Professional C# 4 and .NET 4
Yes, there is a lot of carry over material that's been updated for .NET 4. But the authors also made a big effort to cut older topics that won't be used much and increase the amount of .NET 4 specific feature coverage. Hope this helps.