Muscles do far more than help us lift heavy things off the ground. Muscles make the heart work well and move food through the stomach. They allow us to walk, swim, and even draw! In the fun fact file format, this book introduces readers to the most interesting aspects of the muscular system, including information from the science curriculum, through engaging and sometimes gross tidbits! Detailed diagrams and full-color photographs support each fascinating fact, guiding readers to better body literacy and understanding of this important body system.