One of the interesting things about Android development is that Gradle has been adopted as the build system. Gradle is a great build tool that is useful not just for Android development, but general Java development as well. Unfortunately, Gradle is only briefly mentioned in your book, so I would like to add to the suggestions others have made for future editions. Could you add a chapter on Gradle?
Thanks for putting together your excellent book. I can definitely recommend it for developers looking to learn Android.