Sharks and rays are one of the oldest and most diverse groups of vertebrates, dating back more than 350 million years, and their shape means that they are ideally adapted for life in the world's oceans. This text describes 240 species of these creatures. Each shark or ray entry includes: an illustration and a clear description of what it looks like; details of size, geographical distribution, what it eats and how it breeds; and information on whether or not it is dangerous to humans. The introduction covers the anatomy of a shark, how to avoid a shark attack and details of what measures are being taken to conserve sharks in the wild.