The book itself seemed to make sense but the tools are difficult. I could not tell if they were free or even available as Google constantly changes these things. If you want an introduction to coding go to the Microsoft Virtual Academy. MS may lag behind in the smartphone market but they have the best resources for newbies to learn the skills required to program and develop software and apps.
This book is great if you are new to web app development, or the Google App Engine framework. It starts with the basics of web app dev, and then dives deep into the inticracies of GAE framework. Ofcourse it only covers the Python implementation, and leaves out the Java API's, so it won't help you if you don't code in Python. Otherwise, it is a recommended buy.
This is a well written book that I highly recommend for a beginner on web frameworks and google app engine. The book goes through a simple tutorial of a single project. Each chapter issues a new feature that is then incorporated into the tutorial. The book tackles one thing at a time, which I believe is the best approach for learning a new platform.