Rivers, William Halse Rivers, 1864–1922, British anthropologist. He taught at Cambridge from 1893 until shortly before his death. Trained in medicine and psychology, he pioneered in the experimental study of mental functions among preliterate peoples, making his first field investigations in 1898 among the islanders of the Torres Strait, which separates Australia and New Guinea. Rivers also made a major contribution to social anthropology, introducing the genealogical method into sociological investigations. This method is applied with great success in his classic study, The Todas (1906). An expedition to Melanesia in 1908 resulted in his monumental work, The History of Melanesian Society (1914). His attempts to fuse ethnological facts and psychoanalytic theory led to such works as Instinct and the Unconscious (2d ed. 1922) and Medicine, Magic, and Religion (1924). Other writings include Kinship and Social Organization (1914), Essays on the Depopulation of Melanesia (1922), Psychology and Politics (1923), and Social Organization (ed. by W. J. Perry, 1924).