David Crosby was a consultant general surgeon at the University Hospital of Wales. He was born in Cardiff on 12 November 1930, the son of William Crosby, a salesman who had served as a quartermaster in the RAMC during the First World War, and his wife, Elsie. He was educated at Court Road Primary School, Cardiff, and Bangor Grammar School in Northern Ireland, when his father was posted there. He later went to Cathays High School, Cardiff. He entered the Welsh National School of Medicine, Cardiff, in 1948. In his preclinical years, during a paid student holiday attachment to the Medical Research Council’s survey of pneumoconiosis in the miners of the South Wales valleys, he had contact with Archie Cochrane, who subsequently became professor of tuberculosis and chest medicine in Cardiff. Cochrane took an interest in medical students and, with his sceptical approach to medicine and diagnostic methods, and advocacy of clinical trials, was a lasting influence on Crosby. After qualifying in 1953 and a preregistration year in his teaching hospital, he spent his two years of National Service in the Army in Germany. On his return to civilian life, an appointment as a casualty officer, through the resulting contact with orthopaedics and fractures, inclined him to a surgical career, which he commenced as a surgical registrar at the Morriston Hospital, Swansea. At that period, in the early 1960s, senior registrar appointments were difficult to obtain and, realising that he needed to strengthen his CV, he applied, with encouragement from a local consultant, for a research fellowship with Francis Moore at the Peter Bent Brigham Hospital, Boston. He spent the year there involved, among other things, in research into the efficacy of a series of drugs on the survival of dogs with transplanted kidneys, thus developing operative skill in this procedure and knowledge of the possibilities of organ transplantation. On returning to the UK, he obtained a registrar appointment at Hammersmith Hospital, where work was being done on dialysis, and renal transplantation using living donors had been carried out. He became involved in the surgical side of setting up renal dialysis at a time when it was realised that it, by itself, would put a cumulative load on the NHS, which the development of transplantation might lighten. In 1964 he returned to Cardiff Royal Infirmary as a senior registrar in the professorial surgical unit under Patrick Forrest and, after two years, was appointed consultant surgeon, with the task of establishing renal transplantation in Cardiff, which he successfully did, in conjunction with his colleague in renal medicine. He did not wish to abandon general surgery and he gradually withdrew from the specialty when a second transplantation surgeon was appointed. Previously full-time, he now started doing some private practice and also became involved in the administration of the NHS, of which he remained a devoted supporter, though a critical one, always clear-sighted in seeing its defects and its virtues. He and his anaesthetic colleague, Gareth Rees, fought for and succeeded in establishing an intensive care service in the hospital. From the 1980s, he became interested in how the NHS was run, served on the health authority management team and later was a full member of the South Glamorgan Health Authority. He retired from the NHS in 1995, the year he was awarded the OBE. David Crosby had a critical mind and his liking for argument and debate led him to examining the difficulties and shortcomings of the NHS as it increased in size and complexity. He was a member of a group which, confronted by those proposing that rationing of health care was essential because the NHS could not afford to provide unlimited services, argued that the problem should not be tackled in this way but, rather, by examining closely the efficacy of what was being done and eliminating services which were not of proven value. No doubt this approach was based on his student experience with Archie Cochrane. He was keenly interested in the ethical and legal problems raised by the advances in medicine, including the rationing of care, organ donation, brain death and the position of private practice in the NHS. He approached these questions with a clear and unprejudiced mind, could see both sides of an argument, was adept at arguing a case and would come down on one side or the other. Both verbally and in writing, he could express his opinions lucidly and distinctly, and delighted in doing so in letters to The Times, The Daily Telegraph and other organs of opinion. His success in having these letters printed was doubtless due to their incisiveness. He took an interest in cars, golf and rugby, and was a keen member of the Cardiff Club, where he would lunch with colleagues weekly and indulge in the arguments and discussions he so much enjoyed. After retirement, he did a law degree, was chairman of the Cardiff Medico-Legal Society and served on the Prison Visitor Service. He married, in 1959, Gwenda Harcombe, a senior house officer in anaesthetics at the time. They had two sons, William and Thomas, one a consultant oncologist in Cardiff, and a daughter, Alice. David Crosby died on 1 November 2008 of carcinoma of the prostate.