I (a hardware/software developer and radio ham for some 30 years) bought LEGO Mindstorms for my now eight-year-old son last Christmas. Being a LEGO nut since he was old enough not to swallow the pieces, he's had great fun with Mindstorms since then.
But after you've built the models detailed in the Mindstorms kit, where do you go next? The Mindstorms online help is pretty good, but tiresome to read on the screen, and not the best medium for a youngster. The Alpha Rex etc. are impressive but it's hard for a child to try to make his own models of a similar complexity on the basis of the models in the Mindstorms kit. There is a huge gap between copying ready-made models and learning to create real robots from scratch, and Laurens Valk's book fills that gap perfectly.
As "the missing manual", this book thoroughly explains the NXT hardware and NXT-G software, in enough technical detail to satisfy a seasoned programmer like me, but without overloading someone who is completely new to the technology. That is no mean feat!
The building instructions are of a similar quality to those provided in the all-too-slim Mindstorms manual, and my son was able to follow them and the programming instructions with only minimal guidance from me (usually because we hadn't yet read the accompanying text! :-)
Now, there are several ways to approach this book. To get started quickly, you or your child genius can simply follow the detailed building and programming instructions to create any of the eight robots detailed in the book. My son had almost no trouble doing this: in fact, he first went after the more complex models like the Strider featured on the cover, followed by the very impressive Chimney Climber. If, like us, you're new to the LEGO Technic and Mindstorms systems, you'll be surprised how they can be made to do such remarkable things.
The program instructions feature a simplified overview - essentially a flow diagram - that lets you follow the basic structure of the program and learn about loops, "if-then-else" blocks, etc. Your young robotics engineer can learn about the how-and-why of the programs, and gradually improvise to deepen his/her understanding of what the NXT controller is "thinking", and then devise clever ways to change it.
Then there are the challenges, or "discoveries" to use Laurens' word: 87 of them in all. Once we have settled down to reading the book together start-to-finish (give us a chance, we've only had this book for a week!), the discoveries will provide many new paths to explore and consolidate our understanding of robotic systems.
I would have expected to pay three times what Amazon is charging for this book, based on similar books aimed at software developers. At under $20, it is excellent value for money and an essential "NXT" step on any robot designer's path of discovery. Buy it!