Book excerpt: This is a new, redesigned and reformatted edition of a popular title. Whales and dolphins, or cetaceans, have captivated and intrigued humankind for centuries. They are incredibly diverse and have evolved a fascinating range of specializations to allow them, despite being air-breathing mammals, to exploit habitats ranging from the surface waters to the abyssal depths. Whales and Dolphins of the World is a stunningly illustrated celebration of their variety - there are over 80 species - behaviour and natural history. It describes what we know of their lives such as feeding, reproduction, communication and social structures, and outlines the factors that affect them, from hunting to pollution. The strong relationship between humans and cetaceans is also considered, with a look at dolphin therapy, as are the pros and cons of whale- and dolphin-watching and what makes a good trip. A map of the world highlights the waters in which these mammals are found.