Discover the acrobatic abilities of these lightweight motorcycles. Meet the gravity-defying masters of motocross racing! In this book, readers in grades 4-8 will jump into the rip-roaring, hill-leaping world of dirt bikes! This information- and photo-packed series introduces readers to the coolest off-road vehicles on the market and in the military. Each book in the series revs readers'' engines with amazing details and eye-catching images. These high-interest books feature stand-alone spreads, so readers can flip pages and read in any order. Glossary words are defined on the page where they appear, boosting reader comprehension.