Are sharks really dangerous? How many kinds are there? And how do they help the environment? From huge whale sharks to tiny dwarf sharks, this book has everything you need to know about one of our most popular--and mysterious--sea creatures. Millions of years before the first dinosaurs walked the earth, the first sharks swam in the sea. Though they're often feared and misunderstood, most sharks aren't dangerous to humans. With her signature combination of accessible, kid-friendly text and clear, well-labeled illustrations, Gail Gibbons introduces many of the more than three hundred types of sharks in the ocean, and gives concise information about their habitats and physical characteristics.