Three leading scientific experts on nudibranchs and sea slugs collaborate to produce a comprehensive guide for divers to the Indo-Pacific region. The Indo-Pacific represents the largest expanse of tropical ocean in the world, stretching from the Indian Ocean coast of Southern Africa and the Red Sea to the Central Pacific of the Hawaiian Islands, Easter Island and the Marquesas. This region supports the most diverse marine fauna of any place in the world for most groups of organisms. The opisthobranchs (nudibranchs and other sea slugs) are no exception to this rule. There are about 3000 described species of opisthobranchs in the world and at least 40% of these have been found exclusively in the Indo-Pacific Tropics. This book illustrates 1953 Indo-Pacific opisthobranchs, including many undescribed species. With the evolution of chemical defenses and the loss of the shell, came the evolution of the bright color patterns, that are the signature of nudibranch diversity; vivid colors advertise the presence of toxicity or distastefulness. Other species went down the track of being cryptic, blending in with their surroundings and some evolved amazing strategies of resembling their specific prey. All of this beauty and color is on full display in 2248 photographs on 408 pages.