Book "Animation" by Preston Blair
I've started Animation and Drawing classes this past week and it went really well. The amount of students is growing and I feel I'm doing my part to keep this medium alive and well, although I have to say that most of the principles I teach apply as much to 3D as to 2D. From Phone Apps to Computer Animation to Graphic Design, everything is an expression of the artist that tries to create something that speaks out to oneself or the client and these classes will help develop your skills and approach to whatever you want to do...
After all, it is not called Illusion of Life for nothing.... :)