Stuart Craig Lennox was a consultant cardiothoracic surgeon at the Brompton Hospital, London. He was born on 25 May 1932 in Aberdeen, the son of James Craig Lennox and Agnes Lennox née Hadden. He was educated at Robert Gordon College in Aberdeen and then, from the age of 14, when he moved to London, at Minchenden Grammar School. He studied medicine at the London Hospital Medical School and qualified in 1956. As a medical student, he played football for London University. He was a house officer at the London and Southend hospitals, and then trained in general surgery at the London and in cardiothoracic surgery at the London, National Heart and Brompton hospitals (from 1960 to 1968). In 1961, he was asked to build a hypothermia unit for open-heart surgery in the department of surgery at the London Hospital and to train a team to use it. As a registrar at the National Heart Hospital, he was involved with work on heart and lung transplantation carried out at the Royal Veterinary College. Later, at the London Hospital, he studied mitral valve homografts in dogs. During his training he was awarded an Evarts Graham travelling fellowship from the American Association for Thoracic Surgery, principally at the University of Michigan Hospital in Ann Arbor. There he was involved in animal research, a large part of which was aimed at furthering the development of coronary artery surgery. Other experimental work included the transplantation of lungs in calves. He also gained experience of paediatric cardiac surgery, working principally for Herbert Sloan. He was particularly interested in the problems of open-heart surgery in the infant, and published papers with Sloan on this subject. After his time at Ann Arbor, he toured America, visiting cardiothoracic units in most mainland states. He returned to the USA in 1968, spending several months at the Texas Heart Institute with Denton Cooley. In 1968, Lennox was appointed as a consultant in cardiothoracic surgery at the Brompton Hospital and as a senior lecturer at the Cardiothoracic Institute, University of London. In 1976, he was also appointed as a consultant in cardiothoracic surgery at St Mary’s Hospital, Paddington and, in 1980, at Mayday Hospital, Croydon. He pursued a general cardiothoracic practice, performing 300 to 400 open-heart operations a year. Half of these were coronary artery operations, the rest were for congenital heart disease and valvular disease. He also performed 40 to 50 closed-heart operations a year, mainly for patent ductus arteriosus, coarctations and to insert shunts. He operated on 100 to 150 pulmonary cases a year and, in addition, performed a few mediastinal and oesophageal operations. The Cardiothoracic Institute of the University of London was the only postgraduate establishment dealing solely with the diseases of heart and lung, and as a senior lecturer he had a large commitment to teaching and research. He taught doctors of all levels, including general practitioners, postgraduate students, overseas fellows and overseas consultants, and lectured medical students at St Mary’s, and nursing and physiotherapy students at St Mary’s and the Brompton Hospital. He was also responsible for organising and chairing the annual cardiac surgical course, and for organising the annual Brompton surgical lecture and associated symposium. He established an experimental laboratory in 1967. The research projects included the study of the effect of altering blood flow on growing piglets and its consequences to the growth of their lungs. He also looked into the effect of portopulmonary shunts, producing pulmonary hypertension on growing piglets, and heart and lung transplantation. A number of fellows gained their MDs from this work. Stuart Lennox was involved with various studies concerned with lung and heart transplantation. His particular interest was in studying the denervated pig lung, collaborating with researchers in Turin. In collaboration with V Keerthinathan in Melbourne, the laboratory also evaluated new biological conduits used for replacement of the superior vena cava, as portopulmonary shunts in infants and in coronary artery disease in clinical practice Stuart Lennox was amongst the first surgeons in the UK to perform coronary artery bypass grafts. He taught a number of fellows and registrars, who went on to become leading exponents of cardiothoracic surgery, both in Britain and around the world. He was appointed as a visiting professor to a number of American universities, including Duke, Georgia and New York University, as well as at universities in Europe and Asia, including Malaysia, Australia, China and Russia. He featured in several BBC television programmes, although he did not allow his name to be used. These included a demonstration of coronary artery bypass grafting and the Vineberg operation on *Horizon* in 1969, a demonstration of lobectomy for carcinoma of the lung on *Horizon* in 1973 and of aortic valve replacement for Jonathan Miller’s The body in question in 1978. Lennox wrote more than 100 papers and was asked to write many book chapters. He was an international editor of *Chest*. He was an elected regent of the American College of Chest Physicians (in 1982), an elected member of the American Association for Thoracic Surgery (in 1983) and a council member of the American Heart Association (in 1983). In 1957, he married Brenda Giles, a physiotherapist who had trained at the London Hospital. They had four children, three of whom followed him into medicine. He retired from clinical practice in 1996 and later that year underwent an emergency mitral valve replacement. The surgeon was his former registrar Frank Wells, and the valve had been invented by his good friend Albert Starr. He retired to the country, where he took up golf and developed an interest in sculpture, becoming a guide for the Henry Moore Foundation. Stuart and Brenda’s home became a magnet for their 11 grandchildren and extended family. Stuart Lennox died on 4 August 2018 at home in his sleep. He was 86.