S H Wass, the only child of Isaac Wass of Nottingham, was born on the 5 December 1907. He was educated at University College Nottingham, and came to Guy's Hospital as a preclinical student in 1928. He qualified in 1934, became FRCS in 1935 and MS of London University in 1936. Because of the second world war his appointment to the consulting staff was unduly delayed, and while a registrar he had the opportunity of developing those skills for which he became renowned. From 1937 to 1939 he was a clinical assistant at St Mark's Hospital, and here he evinced that promise of excellence in diagnosis and treatment of diseases of the colon and rectum for which he subsequently became famous. Before his election to the consulting staff of Guy's Hospital in 1946, Wass had already served on the staffs of the Evelina Hospital for Sick Children, St John's Hospital, Lewisham, and St Olave's Hospital, Bermondsey. The immense amount of practical experience which he acquired in these posts was reflected in his work during the course of his professional life. He became the "surgeon's surgeon," and many members of the families of his colleagues owed their lives and their health to his skilful care. In the same year as his election to the staff, Wass was appointed Hunterian Professor at the Royal College of Surgeons and lectured on odontoma and other affections of the jaws. He was invited to lecture and to operate in many centres abroad. As visiting surgeon he went to the Johns Hopkins Hospital in Baltimore, to Cape Town and Johannesburg, and to the Prince Henry Hospital in Melbourne. In all these centres just as at Guy's, he was recognised as a man of wide knowledge, of sound common-sense, and of immense technical skill. These qualities made him an outstanding teacher of basic surgical skills both to undergraduates and postgraduates. For the same reasons, he was much in demand as an examiner, serving on the Court of Examiners of the Royal College of Surgeons for nine years between 1955 and 1964. He also examined in surgery for the University of London. In 1964 he was appointed a governor of Guy's Hospital and in 1966 he was elected Chairman of the Medical Committee and also of the School Council. In 1946 he married June Blaikie. By a former marriage there were two sons, Peter and Michael, and after his marriage to Miss Blaikie two more sons, John and William, the former entering the medical profession. He died in Guy's Hospital on 10 February 1970 from carcinoma of the lung.