Now you can become a junior genius with Ken Jennings' first children's series! With this book you'll become an expert and wow your friends and teachers with out-of-this-world facts: Did you know that Mars has a volcano bigger than the state of Arizona? Or that there's a star with a diamond the size of our moon at its core? With great illustrations, cool trivia, and fun quizzes to test your knowledge, this guide will have you on your way to whiz-kid status in no time!