I bought this book as a companion to Matthew MacDonald's other work on asp.NET 4.0 `Beginning ASP.NET 4.0 in c# 2010" and I have been more than impressed with both works. The beginners book is as the title implies, for beginners, but the depth of this work makes it a complete reference in itself. However for the developer with some understanding of ASP.NET, the pro version is, in my opinion, the definitive work. I have a book shelf full of ASP.NET books, but this one is the one that always stays on my desk.
As always, Matthew has produced a scholarly work, but has also managed to make it readable as well. I would recommend it to any serious developers as a `must-have'.