Learning Processing By Daniel Shiffman
I just bought this book so I can refresh my skills at coding. The trick with Processing is to find the right instructor, and to practice, practice, practice! Daniel Shiffman was one of the most sought-after Computational Media professors at ITP. He teaches ICM (intro class), Nature of Code, and Programming from A to Z, and the Friday Review Sessions for ICM. So he has a lot of experience teaching non-tech people programming. All of those classes were full, and some had waiting lists of 35 people.
He has just written this book, and Amazon is selling it for only $45 or $50. I think if you pre-order it costs slightly less. I say "just only $45 or $50" because a typical class at ITP is or was approximately $4000.00. Now that's a steal.