I was really blown away by this book. Besides the quality of the diagrams and illustrations, which go far beyond any popular mathematics book I've ever purchased, the variety and depth of examples of proof techniques is really impressive. All my old favorites (like tiling a checkerboard and the mxn chocolate bar problem), and many that I've never seen before (a proof that the number of different infinities is not any of the infinities!) are beautifully illustrated and described in accessible but rigorous terms.<br><br>My 7 year old daughter looks over my shoulder when I'm reading this book and asks lots of curious questions. This book has been a great introduction to the beauty and wonder of mathematics for this budding mathematician!