Programming Google App Engine, Dan Sanderson, O’Reilly, 2012
Programmers will like this book. If you want a scalable web app written in Java or Python then the Google app hosting platform is for you. This book explains the architecture and shows how to program to the API. Your app will be responding to requests and generating responses as normal. The big difference is the DB API, because the DB is not relational and does not use SQL. 500 pages.