This book sets a new benchmark for the identification of nudibranchs. It presents nudibranchs that have been photographed by the authors over a period of more than 30 years, along with numerous pictures by contributing diving friends and scientists from around the world. 2500 photos of nudibranchs in their natural environment. Over 1180 species of nudibranchs illustrated. Identification of most nudibranchs known to species level. Relationships between species from different oceans. Information on behaviour (defense, camouflage + mimicry). A comprehensive photo-identification guide to nudibranchs of the world seas.