John Turk was a former professor of pathology at the Institute of Basic Medical Sciences at the College. He was born on 2 October 1930 in Farnborough, Hampshire, where his father was a solicitor. From Malvern, where he specialised in classics, John went up to Guy’s Hospital to read medicine, qualifying with honours and two gold medals in 1953. He did house jobs at Lewisham, where he met his future wife, Terry, and then did his National Service in the RAMC in Egypt and Cyprus, where he developed his interest in pathology. On demobilisation he was appointed senior lecturer at the Institute of Hygiene and Tropical Medicine, working at the Medical Research Council research unit at Mill Hill, going on to be reader at the Institute of Dermatology in the University of London. He was one of the pioneers in clinical and experimental immunology, building on the work of Medawar and Humphreys, and was a founder of the British Society of Immunology. John Turk made important links with deprived and developing nations, where he was able to use his linguistic skills, and became in time an international authority on leprosy. He was appointed Sir William Collins professor of pathology at the Institute of Basic Medical Sciences in our College. The author of many articles, he wrote two classic textbooks, *Delayed hypersensitivity* (Amsterdam, North-Holland Publishing Co., 1967) and *Immunology in clinical medicine* (London, William Heinemann Medical Books, 1969), which became very popular and was translated into many different languages, including Bulgarian and Japanese. In addition he and Sir Reginald Murley edited the collected case books of John Hunter. He was curator of the Hunterian Museum for many years. He was editor of *Clinical and Experimental Immunology* and *Leprosy Review*, was president of the British Society for Immunology and of the section of immunology of the Royal Society of Medicine, and adviser to the World Health Organization on leprosy. His wife Terry was a general practitioner; they had two sons, Simon and Jeremy (a psychiatrist), and three grandchildren. A delightful companion, John Turk was a kind and sensitive man, and a devoted servant of the College, who made him FRCS by election. He suffered from diabetes and died from renal failure and small vessel cerebral disease on 4 June 2006.