Thump-Thump - Who's There? It's your heart-your body's busiest little helper! In this anatomy book: Hello, Heart! The Busy Pump Inside You, kids will laugh, learn, and feel the beat as they meet the hardest-working muscle in their body. With fun facts, silly illustrations, and playful storytelling, this book makes anatomy exciting for young readers ages 3-8. From racing during tag to relaxing during bedtime, your heart never stops working-and now it's ready to tell its story!