Origami Design Secrets-Mathematical Methods for an Ancient Art by Robert J. Lang.  The magnum opus of one of the world's leading origami artists, the second edition of Origami Design Secrets reveals the underlying concepts of origami and how to create original origami designs. Containing step-by-step instructions for 26 models, this book is not just an origami origami cookbook or list of instructions-it introduces the fundamental building blocks of origami, building up to advanced methods.