To be used with the Lego Mindstorms NXT robotic set, these two hefty guides provide much information about building and programming. For those of you who don't know, "the NXT set is a robotics toolset designed by the LEGO Group that empowers users to create functional robots entirely out of LEGO pieces." The set includes LEGO Technic pieces to build robots, sensors and motors to control the robot and let it sense the world around it, and a microprocessor that controls the sensors and motors. Also included are Mindstorms NXT software and a USB cable to connect the computer with the robot. Windows XP or Windows Vista or Mac OS X version 10.39 or 10.4 is a requirement.

Along with some great introductory material, the meat of these books is the plans and programs they take you through. To use these guides one needs a Lego Mindstorms NXT set. For The Lego Mindstorms NXT Idea Book you need to have the retail version or the education version plus the Education Resource Set.

The Unofficial Lego Mindstorms NXT Inventor's Guide is divided into four parts: an introduction, building tips, programming the NXT, and six projects. These are zippy-bot vehicle, bumper-bot, claw-bot (pushes not grabs objects), tag-bot (a self-guiding robot that avoids objects and plays flashlight tag), guard-bot (a six-legged walker), and golf-bot (uses a sensor to hit a ball to a target). There are also three useful appendixes (a piece library, programming icon index, and internet resources) and what every good non-fiction book should have: a thorough index.

This book "assumes no previous experience with LEGO or Mindstorms, but it also offers advanced material to challenge skilled Mindstorms users. In addition, this guide can serve as a helpful reference for all readers." My 12-year-old son concurs, saying this is more of a basic guide, teaching you how to use the Mindstorms as well as how to improve your skills. Incidentally, LEGO Mindstorms is for ages 10+.

An interesting footnote: Author David J. Perdue says in the acknowledgement, "I recognize most of all that this book is the result of God working in my life. He faithfully guided me every step of the way and always strengthened me to take the next step. I offer this book to my Lord and Savior Jesus Christ."

The Lego Mindstorms NXT Idea Book is the work of eleven authors, including a 15-year-old. (Their individual bios make interesting reading themselves!) It is divided into two sections. Part 1, aptly entitled "Beyond the Basics," has a rundown of the building pieces, programming basics, trouble-shooting help, information on sensors, design tips, using Bluetooth with Mindstorms, and NXT to NXT remote control.

Once again, the highlight of the book is part 2, designs and instructions for building 8 robots: a rock-scissors-paper playing robot, a ramblin' "beach buggy" robot, a 3D photo assistant robot, a grabber robot, a slot machine, an anti-theory music robot, an image-scanning robot, and a performance art robot. The two appendixes offer information on the differences between the retail and educational version of the LEGO Mindstorms kits and a CAD installation guide. Once again, there is also a comprehensive index. It should be noted that that the 3D photo assistant robot requires a digital camera and the slot machine requires more pieces than one LEGO Mindstorms kit contains (as noted in the book).

Who is this book for? According to the introduction, the authors ‘'assume that you have some familiarity with building and programming with the NXT." It is indeed an idea book for those who have more experience with LEGO Mindstorms.

The format for each robot design in both books is similar. After a bit of text, there is a diagram of all the components needed, the instructions for building the robot, and then the programming instructions and how to use what you've made. The Lego Mindstorms NXT Idea Book also includes trouble-shooting tips and ideas for going beyond or learning more about the robot and program.

My son noted that both books have downloadable programs. However, The Unofficial Lego Mindstorms NXT Inventor's Guide directs the reader to this website at the beginning of the programming instructions for the first robot, whereas The Lego Mindstorms NXT Idea Book clues the reader in to their website for downloadable programs very discreetly at the end of the book.

I give both books a high rating for usability and interest and recommend them to anyone who is a fan of Lego Mindstorms. Keep in mind that The Unofficial Lego Mindstorms NXT Inventor's Guide is a better choice for the beginner and The Lego Mindstorms NXT Idea Book is an idea book for the more advanced Mindstorm student.

Product review by Kathy Gelzer, The Old Schoolhouse® Magazine, LLC, April 2008