First of all, the book is for developers, not for designers. It is written by a 360 degree expert, who also wrote books on ASP.NET and WPF. The author, from a developer's perspective, eliminates doubts as they arise from complex related topics. For those who are also interested on WPF, you are always warned where and when thing work differently in Silverlight, with precious and ubiquitous "WPF VS Silverlight" inserts. Each topic is deeply explored and well explained, often revealing internals of Silverlight's client and host ecosystem. The good thing is also that these practices are cross-browser and cross-platform; this means the power to target more users with your application. If such a target is in your plans, this is a must have for your bookshelf and a great companion for its big brother book on WPF.