Muscles help us move from place to place, but they also help important parts of our bodies work, keeping us alive and well. This engaging volume helps readers of many ages and levels understand how the muscular system works, from its processes to the different kinds of muscles humans have. Accessible text supports lower-level readers. Eye-catching images and interesting fact boxes emphasize key concepts related to upper elementary science curricula. This informative guide makes an excellent supplement for readers studying the human body.