Volume 1 of App Inventor 2: Tutorial is available at Amazon.com.
Volume 2 is in development and will cover a lot of the Android features – like camera and database usage – key elements to create real-world applications.
Volume 2 is completely outlined. But before I start writing, I am creating a moderately large sample application to be used for the examples in the text. Design of the sample application is under way.
I am also working on video tutorials for learning App Inventor 2 – these will end up on Youtube as they get completed.