This book is specifically geared toward readers who have been actively developing solutions in ASP.NET and Silverlight 2 or 3. This book is not a primer on either of these two technologies. Instead, you will see how to make use of enhancements to the latest version of Silverlight in order to create a Rich Internet Application. In general, I will not be covering in great detail how to develop in Silverlight or the related ASP.NET technology that is required for all Silverlight-based solutions. There is specific coverage of the ne w features in Silverlight 4 including WCF RIA Services and the new Silverlight Toolkit. In order to get the most out of this book you should have a good understanding of how to use all of the existing Silverlight controls. w features in Silverlight 4 including WCF RIA Services and the new Silverlight Toolkit. In order to get the most out of this book you should have a good understanding of how to use all of the existing Silverlight controls.