Athol George Riddell was born in Whitstable on 31 January 1917. He was educated at Folkestone and University College, London, where he gained the Gold Medal in physiology, graduating from University College Hospital Medical School in 1939. After holding a resident surgical post on the Professorial Unit there he entered the RAF Medical Service, where he remained until 1946 in the rank of Squadron-Leader. For his work on malaria in India during this period he was appointed MBE. Returning to University College Hospital after the war, he became successively surgical registrar, John Marshall Fellow in surgical pathology and resident assistant surgeon in the years 1946-62. He obtained the FRCS in 1948. In 1952 he was awarded a Bilton-Pollard Travelling Fellowship and spent two years at the Massachusetts General Hospital as a research fellow and fellow in clinical surgery. There he came under the influence of two men who determined the future course of his life. These were E D Churchill, whose example inspired him to seek a career in academic surgery, and William McDermot, who gave him an abiding interest in the problems of the surgery of the liver. He was awarded the MS London for his thesis on liver disease on the work he did there. From 1955 to 1964 he worked in the department of surgery of the University of Manchester, first as lecturer and later as reader. In 1964 he was appointed to the Chair of Surgery at Bristol. Here he continued his work on liver surgery and laid the foundations for a programme of experimental liver transplantation and preservation and storage of the liver. At this time he became interested in the immunological aspects of malignant disease and especially in the preservation of human spleen cells and their application in the treatment of cancer. Undoubtedly his greatest achievement at Bristol was the complete reorganization of the undergraduate curriculum. The development of an integrated programme of teaching which surmounted all the usually accepted departmental barriers was largely due to his enthusiasm and leadership, and he threw all his energies into the project. Though he worked long hours on clinical and administrative duties he gave much of his spare time to the welfare of his staff and spared no effort to ensure that his trainees received appropriate and personal guidance. A member of the South-Western Regional Hospital Board, he was appointed to the new regional health authority and also served on the Department of Health's advisory panel on transplantation. He was an examiner in surgery to the Universities of Manchester, Bristol, and Leeds, and for the Royal College of Surgeons of England and the Royal College of Surgeons in Ireland. The breadth of his surgical interests was shown by his membership of the New York Academy of Sciences, the Association of Surgeons, and the Society of Thoracic Surgeons, among many other affiliations. Athol Riddell was a powerful personality and his greatest characteristics were his intellectual honesty and personal integrity. He was basically a shy person and only those who got to know him well could really appreciate his appealing qualities as a friend. An evening spent in his company was a stimulating and amusing affair of intellectual cut-and-thrust which would have gone down well at a high table. He was a golfer of considerable prowess. From his father he had acquired a wide interest in natural history. In earlier years his interests had centred on lepidoptera, and he amassed a comprehensive collection of moths. Later he became a member of the Alpine Garden Society and applied the same devotion and enthusiasm which characterized his professional work to the nurturing of these rare and temperamental jewels. He had created a beautiful alpine garden at his home in Clevedon, and he died when its beauty was at its height. He married Valeria Wiltshire in 1946 and they had two sons. He died suddenly on 11 May 1974, aged 57.