I have read the second edition as well. The third edition carries on from there and provides a deeper look in C# 5 and it’s key feature async/await. If you want to understand what goes on behind the scenes, this one is for you. Jon Skeet ( yes the famous guy Jon Skeet) has managed to come out with a great book once again.
Jon starts easy on this, but doesn’t hold back. The prose is lucid yet well paced. It is one of the few books that make the effort to take the reader on journey. The journey begins with C#1 and then continues to C#5. Hardly any chapters drag on anymore than they should. Linq is covered in great depth and is a nicely written with enough diagrams to visualize what is happening under the hood. Generics is one my personal favourites. The text is nice, so are the code samples. I have never really understood generics completely, but the books does make things a lot clearer. The treatment of dynamic is really nice. It goes into the heart of the DLR and shows everything that you need to know to really understand dynamic.
The book really shines when you move to async/await. Jon makes a rather tough concept easier. I had to read it several times but each time the concept became easier. I only wish we moved away from the download the web page example for async. The book does spend time on compiler transformations that are behind async/await. Be patient when you read it, it will take time to sink in.
The only part that has been left out from the third edition is the chapter on Code Contracts. Jon clearly mentions that the topic hasn’t gained as much traction as he hoped. It may come back in the future though. As many have mentioned this before this is not a book for beginners. Use this to become a better C# programmer, after you have written C# for some time. This is a must have in your collection, especially if you work with C# day in and day out. It will give you a greater understanding of how the language designers wanted you think, and what makes C# a real joy.
A 4.5/5 for this one, keeping the 0.5 for the next edition :).
P.S. Even the appendix is handy.
Disclosure : I got a free copy of the book to review. The review is my own opinion and not influenced by anyone else.