The book The Secret World of Flexagons: Fascinating Folded Paper Puzzles is now available at your favorite bookstore or directly from the publisher.

From the introduction: "Flexagons sit at the intersection of paper folding, puzzles, and mathematics. You could choose to enjoy the pleasure of using your hands to flip through a kaleidoscope of arrangements. Or come up with interesting ways to decorate them. Or explore what's hiding inside, possibly discovering new flexes and new types of flexagons. Or challenge yourself to figure out how to "solve" a flexagon in the same way you might solve a Rubik's Cube. Or investigate the mathematics that can untangle how the twisted strips of paper actually work. In this book, we touch on each of those areas, leaving it up to you which of these most interest you."