I can repeat here what I wrote about the book "Pro Silverlight 2 in C# 2008", by the same author: this book in my opinion is very clear, precise, well written.
I saw many books about Silverlight 2, but "Pro Silverlight 2" stands as the best I ever read.
As an MCSD, I was looking for a book not talking about .NET primers but specifically about Silverlight. And this book had exactly that formulation.
As an MCT, I was looking for a didactic book, possibly useful to provide knowledge to my collegues. And this book was perfect in those aspects.
I loved the included samples, that I used to call "building-block samples", because they are not submerged into complex and hard-to-understand big demo projects, but are standing on the specific topic the author is talking about.
I used the "C#" version of this book as a base for a 25-hours internal course for my collegues and, well... it was a real triumph: I think part of this success is indirectly due to the excellent work by the author.
In my opinion, this book is a must-have. I will not miss the next Matthew's book on Silverlight 3.