O'Reilly Media book: Programming Google App Engine

Programming Google App Engine:

Google App Engine does more than provide access to a large system of servers. It also offers you a simple model for building applications that scale automatically to accommodate millions of users. With this updated edition of Programming Google App Engine, you'll get expert practical guidance that will help you make the best use of this powerful platform. Google engineer Dan Sanderson shows you how to design your applications for scalability, including ways to perform common development tasks using App Engine's APIs and scalable services.