I love the variety of puzzles in this book. They range in difficulty - my 10-year-old son, myself, and my physics-adoring husband have all been challenged and entertained by the puzzles in this book. I love that the author says at the beginning of the introduction, "If you really get stuck, don't give up - or you'll spoil the fun. Put the sticky puzzle aside, and perhaps the next day a new line of attack may suddenly strike you. Or you can try to solve an easier puzzle similar to the sticky one. Or again you can guess trial answers just to see if they make sense."
He does give the answers at the back, but he's right; it's much more satisfying to figure it out oneself.
The puzzles are grouped by type; the easier ones at the beginning of the section, gradiently getting more difficult.
This book is really wonderful for children and adults. As a homeschooler, I find this a wonderful tool for challenging myself and my kids. It's a great tool for making math FUN!
