About the Book Licenses
The book contents are licensed under the Creative Commons Attribution-ShareAlike 4.0 International license.
You are welcome to use and distribute the books, in their unmodified original form, as you see fit. If you adapt the work — including converting to other formats, modifying its contents, and translations — you need to make the adaptations available under the same license or a compatible license.
In addition, the source code shown in the books is licensed under the Apache License 2.0. You may use the source code as you see fit within the confines of that license, which is the same license as is used by the Android SDK and many popular open source libraries for Android.