I own the first Idea book, the Inventor's Guide and I pre-ordered the One-Kit Wonders book, which arrived a week ago. Its projects are probably the best of the 3 books. Very doable, challenging, but they are very, very well designed and once finished, they work very well. They are a lot of fun to build for me and my 9-year old. This book is different to the two others mentioned here, because it goes directly into the projects without any introduction to Mindstorms building or NXT-G programming tutorials. So the content is fully dedicated to the projects. The download section of the blog forum is working OK, so now you can download the programs. And last but not least, when you get stuck at some point, you can always count on the forums for help. I posted a question and one the the co-authors replied to me within a few hours, with a solution. The book is the "tip of the iceberg" because there is a community around it that goes beyond the printed works.The only wish for this middle-age reviewer (with a middle-age eyesight) is building instructions in glorious Lego colors. As in the other books they are in greyscale. To the credit of the authors, they did poll their readership in the blog about this when the book was still in the works, and the result was overwhelmingly in favor of B&W to keep the cost down.This book makes my Mindstorms NXT experience so much enjoyable that I rate it with five stars.