His book is about mathematics and origami. In part one it is shown. It's called Project Origami (Activities For Exploring Mathematics). It's not a "how to make a bunch of stuff" type book; there's tons of other books for that (and RU-vid videos). It's written especially for math teachers but it's also an excellent study guide- it's got very easy to fairly difficult origami and easy geometry up to higher mathematics like abstract algebra.
