Considering how little information there is out there on WPF, it is no surprise that I eagerly read Windows Presentation Foundation Unleashed by Adam Nathan, especially considering how much I appreciated his previous book on .NET/COM interop. I was hoping for more depth and less breadth, but I think I'll have to wait for someone to write "WPF Internals" for that. Otherwise, this book was quite good; I especially enjoyed the full color code samples and screenshots. This book makes a good companion to Petzold's book, since it teaches different things and takes a different approach. I certainly recommend it to all WPF programmers.