This book is about building robots using Lego bricks and components. In the first section of the book (Part I) we will discuss why you might find an interest in robotics as a hobby, and why Lego is an ideal system to have a fast start and great results. If you’re reading this book you probably own a Mindstorms set, so you already have an interest in robotics, and for this reason we kept this part very short. Nevertheless you might find there some thoughts about what robotics can give to you and your family, besides a lot of fun. And how it can change your perception of the environment that’s around you. The second section (Part II) is about how to build a robot. Here we provide a set of tools you need to explore the world of robotics. Some basic knowledge about mechanics, motors, sensors, pneumatics, navigation, and many tips and tricks. We will compare different standard architectures, discuss solutions to common recurring problems, learn how to organize complex projects in terms of subsystems. In the third section (Part III) we start to face the tough question, the one we actually would try to answer with this book: “I got a Mindstorms kit, I have learnt how to use it, what do I build now?”. Here we will show you a large survey of possible ideas, but do not expect to find complete models to copy step by step. 8-Page Full Color Insert The 8-page, full color insert will contain detailed photography of the most impressive robots that readers will be able to build after reading the book. The photos will also detail the more complex electrical and construction challenges.