There are now several books out focusing on Processing.
Processing.org’s own page regarding books highlights quite a few:
- Reas, C. and Fry, B. (2010), Getting Started with Processing, O’Reilly Media;
- Reas, C. and Fry, B. (2007), Processing: A Programming Handbook for Visual Designers and Artists, MIT Press.
- Shiffman, D. (2008), Learning Processing: A Beginner’s Guide to Programming Images, Animation, and Interaction, Morgan Kaufmann
Shiffman’s book has its own dedicated page: http://www.learningprocessing.com/
The recent Form+Code book by Casey Reas also features many examples, including code, done in Processing: http://formandcode.com/
- Reas, C., McWilliams, C. and LUST (2010), Form+Code in Design, Art, and Architecture, Princeton Architectural Press