William Walters Sargant (24 April 1907 – 27 August 1988) was a British psychiatrist who is remembered for the evangelical zeal with which he promoted treatments such as psychosurgery, deep sleep treatment, electroconvulsive therapy and insulin shock therapy. Sargant studied medicine at St John's College, Cambridge, and qualified as a doctor at St Mary's Hospital, London. His ambition to be a physician was thwarted by a disastrous piece of research and a nervous breakdown, after which he turned his attention to psychiatry. Having trained under Edward Mapother at the Maudsley Hospital, he worked at the Sutton Emergency Medical Service during the Second World War. In 1948 he was appointed director of the department of psychological medicine at St Thomas' Hospital, London, and remained there until (and after) his retirement in 1972, also treating patients at other hospitals, building up a lucrative private practice in Harley Street, and working as a media psychiatrist. Sargant co-authored a textbook on physical treatment in psychiatry that ran to 5 editions. He wrote numerous articles in the medical and lay press, an autobiography, The Unquiet Mind, and a book titled Battle for the Mind in which he discusses the nature of the process by which our minds are subject to influence by others. Although remembered as a major force in British psychiatry in the post-war years, his enthusiasm for discredited treatments such as insulin shock therapy and deep sleep treatment, his distaste for all forms of psychotherapy, and his reliance on dogma rather than clinical evidence have confirmed his reputation as a controversial figure whose work is seldom cited in modern psychiatric texts.