This book reviews the origin, development, morphology, environment and ecology of the world's coastal lagoons. There are particularly extensive series of lagoons - areas of salt or brackish water separated from the adjacent sea by a low-lying sand or shingle barrier - along the eastern and Gulf of Mexico coasts of the USA, in Mexico itself, in Brazil, West Africa, Natal, southern and eastern India, south-west and south-east Australia, Alaska, Siberia and around the shores of the Mediterranean, southern Baltic, Black and Caspian Seas. In several of these areas they support important fisheries. This book summarises what is known of the formation and fate of lagoons, the lagoonal environment, lagoonal ecology, the strategies of lagoonal species, the human use of lagoons, besides containing a general introduction and a section on methods for the study of coastal lagoons.