Silverlight 3 Jumpstart by David Yack, Microsoft Silverlight MVP, is a small book designed to get you started with Silverlight. I think it was the first Silverlight 3 book available.
I really enjoyed reading this book, I like the format and the fact that it goes straight from XAML introduction to MVVM in less than 200 pages! The author doesn’t spend too much time explaining what a Rectangle is and how you can animate it… (we don’t really care, right) and focus more on features that will help you build RIA business application.
I really like the chapter on architectures presenting an overview of MVVM, Prism, CLSA, IdeaBlade and .NET RIA Services! I gives you a good starting point to learn about these new framework/pattern.
I definitely recommend this book for any .NET developer willing to quickly become up to date with Silverlight 3; in fact, as a Silverlight Trainer myself I bought several dozens to give to my students.
Note that this book is a premise of a next book focused even more on building business applications using Silverlight, so keep an eye on www.slria.com…