Train Positive Dog!

The Dog Decoder app – available from iTunes for a few dollars, has over 60 illustrations of canine body language with coherent explanations of the behaviors.  Categories of behavior include: emotional states, greetings/friendly, calming signals, stress signals, prey and play drive, and space invaders.  The excellent illustrations are by Lili Chin.   It also has a quiz and a glossary.  Featuring a black and tan dog named Diamond in varied situations with other dogs and people.
I like this one!