Eoin Aberdeen was born in Melbourne in 1924 and qualified in medicine there in 1948. Before coming to England in 1955 he was a medical and surgical registrar at the Royal Children's Hospital and a flying doctor in North-West Australia. After a spell in the burns unit at Birmingham he became surgical registrar in the thoracic unit at Great Ormond Street having passed his FRCS in 1956. He returned to Melbourne to continue his paediatric surgical training but soon returned to the Hospital for Sick Children in London as senior registrar in the thoracic unit. After a year in the United States with Dr Frank Gerbode at Stanford University he returned to Great Ormond Street where, in 1963, he was appointed consultant thoracic surgeon. His work there concentrated on open-heart surgery in infants and small children. He was a perfectionist; each case was meticulously investigated preoperatively, complete and detailed records of all procedures were made and he concentrated on achieving a high standard of postoperative care. His work, especially on transposition of the great arteries, brought him international fame. In 1971, at the height of his success, he left Great Ormond Street for the United States where he felt he would have better opportunity to pursue his interests in measurement and documentation, in particular in the management of complex congenital cardiac anomalies. He was first, chief of cardiac surgery at the Children's Hospital, Philadelphia, from 1971 to 1974, then in similar posts at Mount Sinai Hospital, New York (1974-76) and the Children's Hospital, Newark (1976-78). When he resigned his post at Newark he decided to quit cardiac surgery altogether and in 1980 took a post as emergency-room physician at the Medical Center at Syracuse University. His failure in the USA was partly self-inflicted. He was a highly intelligent man with an almost encyclopaedic grasp of paediatric and cardiac surgery. By means of computerised data storage and retrieval he had built up an unrivalled collection of relevant articles, each carefully annotated. His readiness to compare results of surgical treatment did not always make him friends but he never spared himself criticism. In 1983 he was stricken by severe illness which added to his troubles but he bore all with courage, resignation and humour. He died on 24 March 1986 aged 62. He was supported throughout by his wife, Virginia who survived him together with their two daughters and one son.