I picked up a good book the other day called "Hello, Android: Introducing Google's Mobile Development Platform" by Ed Burnette.
I'd say this book is for beginners and advanced users learning Android for the first time.
The thing I look for in a good book is practical examples. And this book has some good ones. It goes from UI layout (User Interface), 2D graphics, Audio/Video, Data storage, Internet, GPS, SQL (database managment), and even OpenGL 3D.
It dosn't get too deep into anyone one subject but that keeps the book light and easy to understand. And once you've compleated the book you'll know enough to be able to look things up via google's Android database and understand them.