App Inventor: Create your own Android Apps, published by O'Reilly in 2011, is now available in PDF form here at appinventor.org. The links to the right get you to PDF versions of each chapter, or to a page with the PDF and accompanying video lessons. The book was written by USF Professor David Wolber along with App Inventor creator and MIT Professor Hal Abelson and Google engineers Ellen Spertus and Liz Looney.The book is designed for absolute beginners but also useful as a reference to programmers looking to add App Inventor to their arsenal.
The book is organized in a way to motivate learning. The first section walks you through the creation of twelve successively more complex apps that you can build and customize. Find something you'd similar to what you'd like to build and go for it. The apps section is followed by a separate "Inventor's Manual" section which explains programming and computer science concepts in layperson's terms. This section is organized by programming topic as in a traditional text.
Interested in building apps but don't have a year to learn Java? Teaching an introductory (CS0) computer science course to K-12 or university students? This book is for you!
The paperback version is a great companion to app building-- you can use the book to read the tutorial and save your screen for all of the App Inventor windows. Buy it cheap at Amazon!
Note: A new version of App Inventor was launched in December, 2013. We are working on a 2nd edition of the App Inventor book for the new AI version and plan to have it out by August 1, 2014 (you can preview it here). The components and blocks in the two AI versions are basically the same, so the samples in the original book are still helpful in learning App Inventor, but App Inventor 2 and the upcoming book are definitely the way to go.
Looking for help with AI2? Some of the book chapters have been converted!