This book on Silverstripe is written by a new author on this field, Phillipp Krenn. Though his skill set (as available on his website) shows a far wider spread than what I would expect from a Silverstripe enthusiast, the book shows that he is definitely not new to Silverstripe.
Krenn is currently finishing his double master in Software Engineering & Internet Computing and Information & Knowledge Management at the Vienna University, and his knowledge of programming concepts and theories shows; he smoothly guides the reader through the Silverstripe system and highlights its ORM features and clean object oriented structure.
The book does show some similarities to the official Silverstripe book by Ingo Schommer (I read the German version in 2009), in that it approaches the Silverstripe novice and explains the system in its entirety. Having worked with Silverstripe since 2007, this is off course superfluous for readers like me, but essential in a book of this kind, especially as it is only the second book available on Silverstripe.
While I really liked Schommer's book I feel that Krenn's book touches some more general needs and considerations for building a site or a web application. Furthermore it comes in very handy that the book is only recently published, and contains up-to date information, as well as it introduces how to base a Silverstripe site purely on HTML5.
If you'd like to learn about Silverstripe, or you'd like to improve your Silverstripe knowledge today, I'd recommend this book over Schommer's.
Foremost because of its recent publishing, and thus inclusion of 2.4 only features as partial caching and short codes, as well as up-to-date information on error handling and logging, and information on Silverstripe's recent activities regarding structure changes.
But secondly also because of the website example built throughout the book, giving the reader an easy-to-adapt blueprint for whatever website he's working on.