Pro WPF and Silverlight MVVM: Effective Application Development with Model-View-ViewModel by Gary Hall
The book is well written, easy to read and informative. While some technology books can be so in-depth and written so technically as to make them unreadable, thankfully this author has struck a good balance between technical detail and readability.
While there are books that cover Silverlight and WPF in great detail, this isn’t one of them. The author does however give a very good overview of both, giving enough detail of the technologies to form a base for discussion and whet the appetite for more. For instance, the coverage of areas such as databinding and dependency properties are enough to give an understanding of how they work and can be used in the context of MVVM without delving into excruciating details.
The book also has a good generalized discussion of some OO concepts and design patterns such as the command and mediator patterns. Again, it is not in-depth but does give a good understanding of the topics for novices and perhaps a refresher for more experienced developers.
Overall, if you are purchasing this book to specifically learn MVVM it will be a disappointment. If, however, you want a book that offers a general discussion of topics such as validation, data access layers, unit testing and design patterns with Silverlight and WPF with an MVVM bent, then this is the book for you.