I really enjoyed this book. I took it on a long airplane trip with a three-foot length of rope and entertained myself for hours learning the knots, what they are used for, and why they are better than other knots for particular purposes. It's probably literally true that there are 100 knots described in the book, but many are variations of a basic knot. The instructions and diagrams are easy to understand and follow, as are the history and physics of the knots. Plus the book is physically small and flexible, so it's easy to take along.