The 89 species of the order Cetacea are some of the most diverse, intelligent, and elusive animals on the planet. Highly migratory, they live beneath remote skies thousands of miles away from land. The huge distances they cover and the depths they dive mean we catch only the merest glimpse of their lives. Technological advances have, however, increased our understanding, and this book gathers together all the most interesting new research to offer detailed profiles of each species, alongside the information needed to identify them.