John Hamilton Wyllie was professor of surgical studies at University College London (UCL). He was born in Dumfries, Scotland, the eldest son of Andrew McNae Wyllie and Marjorie Hamilton née Maxwell. On his father becoming physician superintendent of Royal Cornhill Mental Hospital, Aberdeen, John completed his secondary education at Aberdeen Grammar School, winning a bursary to Aberdeen University, where he studied medicine, intercalating a BSc and graduating with honours in 1957. He did almost all of his surgical training in Aberdeen, gaining his fellowships of the Royal College of Surgeons of England and the Royal College of Surgeons of Edinburgh in 1964. Research included the study of gastrin secretion (for an MD, awarded in 1961). He was appointed to the Harkness fellowship (funded by the prestigious Commonwealth Fund of New York) at the University of Washington, Seattle, USA, where he worked with Henry N Harkins and Lloyd M Nyhus. He then moved to London, first as Wolfson lecturer at the Royal College of Surgeons of England and an honorary senior surgical registrar at King’s College Hospital (1966 to 1968). He was appointed as a senior lecturer in surgery at University College Medical School in 1968 and as an honorary consultant from 1969. He became a reader in surgery at University College Hospital Medical School, then professor of surgical studies at University College London in 1976. In 1982, he moved to the Whittington Hospital in Highgate (a campus hospital of University College Medical School) in order to establish an academic presence there. He was lead consultant in surgery at the Whittington from 1991 to 1993, and sub-dean of University College London from 1986 to 1989. He was an active and successful researcher; he worked with two Nobel prize winners, Sir John Vane and Sir James Black. He was a keen student of pharmacology and contributed to the development and clinical trials of H2 antagonists, which (as he was keen to point out) radically reduced the need for gastric ulcer surgery. He published widely on gastric pharmacology, prostaglandins, H2 antagonists and surgical education, including key papers in *Nature* and *The Lancet*. Publications included ‘Inactivation of prostaglandins by the lungs’ (*Nature* 1970 Feb 14;225[5233]:600-4), co-authored with Priscilla Piper and Sir John Vane. Sir James Black wrote in his autobiography: ‘John Wyllie, surgeon from University College London, contributed the last critical piece in a successful mission.’ He was a general surgeon with a subspecialty interest in oesophageal surgery, and a notable expertise in achalasia, on which he worked with his long-term collaborator David Edwards. He was an early adopter of fine needle aspiration in the diagnosis of breast disease. John was a much respected as an undergraduate teacher and assessor, chairing the examiners in surgery at UCL from 1991 to 1997. While a committed educator at all levels, he did prefer to teach undergraduates over postgraduates because, in his own words, ‘With the young you can tell them the truth which is that we are unbelievably ignorant of everything that matters’. That uncompromising, humble search for truth, scientific or religious, was a hallmark of his life. In addition to examining undergraduates at University College, he held examiner roles for the LDS at the Royal College of Surgeons of England (from 1970 to 1976), the BDS at the University of London (1974 to 1981, and as chair from 1979 to 1981), the MB BS, University of London (1977 to 1997), the MS thesis panel University of London (1976 to 1997), the final FDS, Royal College of Surgeons of England, 1981, as chair of the MCQ (multiple choice questions) panel at the University of London (1993 to 1995) and various other examinations activity across the world, including in Libya and at the University of Jordan. He also made a contribution as a member of the MCQ panel for the Professional Linguistic Assessment Board examinations for the General Medical Council. He was visiting professor to the University of Illinois, Chicago in 1974, the Al-Fateh University, Tripoli in 1977, the University of Benghazi in 1980, the University of Ghana, Accra in 1985 and Inselspital, Bern, Switzerland in 1994. After retirement in 1997, John moved to the Moray Firth, where he enjoyed honing his programming skills with Open University courses, singing in church choirs and sailing extensively on the west coast of Scotland with his wife in their small yacht. Remarkably his medical career finished where it had all begun – in Aberdeen; until compulsorily retired at 70, he did regular breast clinics there. John died of coronavirus on 11 April 2020 aged 86, in Great Finborough, Suffolk. He was buried in Linton Cemetery, Cambridgeshire, where, due to restrictions imposed by the pandemic, his funeral service had to be conducted in the open air, attended only by ten of his closest relatives. He was married to Kathleen Ruth (née Mackay) and was survived by his widow and three children, David (a doctor), Julia and Ian.