Between the late Victorian period and the First World War, doctors took over control of administration from the founding governors and new techniques and therapies emerged. This period was dominated by Almroth Wright, George Bernard Shaw's model for Colenso Ridgeon in The Doctor's Dilemma, who was knighted for his work on typhoid vaccine. In 1912 Wright delegated the teaching of bacteriology to his assistant Alexander Fleming.

Far-reaching changes at St Mary's followed the appointment of Charles Wilson as dean of the medical school in the early 1920s. Although it was he who persuaded the medical staff to institute academic departments of medicine and surgery, he is perhaps more widely remembered for his belief that the ideal characteristics for entry to the medical profession were to be found in rugby players from public (i.e. private) schools. One of the school's non-rugby sporting heroes was Roger Bannister, the first person to run a sub-four-minute mile—an achievement whose 50th anniversary we celebrate this year. Sir Roger, who won separate distinction as a neurologist, contributes a foreword. Strangely, Elsbeth Heaman makes no mention of probably the greatest all-round sportsman ever at St Mary's—'Tuppy' Owen-Smith, a Capetonian who went to the hospital with a triple blue from Oxford (cricket, rugby, boxing) and played cricket and rugby at international level. With the Second World War came the appointment of George Pickering to the chair of medicine, to which he brought an ethos of research in a hospital previously entrenched in clinical teaching. Among the notable doctors lost by St Mary's to the war were Ivan Jacklin and Peter McCrae, both of whom perished in the notorious Murmansk convoys. Towards the end of the war talk began to turn to the Beveridge Report of December 1942. Earlier in the same year the socialist gynaecologist Aleck Bourne had given a series of lectures on 'The Health of the Future'. Bourne had come to the public eye in 1938 when he terminated the pregnancy of a 14-year-old girl who had been raped by a guardsman—an event that ultimately led to a change in the laws on abortion. The introduction of the Emergency Medical Service, combined with military service for all newly qualified doctors who were fit for it, may well have made young clinicians more receptive to the National Health Service in 1948 than their senior colleagues, many of whom were opposed to it in principle. The Government needed the good will and cooperation of the medical profession and, in the words of Elsbeth Heaman, 'That good will was marshalled and delivered by Charles Wilson, later Lord Moran'.

In 1944 there was a major crisis when the Goodenough Report decreed that a teaching hospital must have at least 700 beds—twice the number at St Mary's. In the end, this difficulty was overcome by incorporating several specialist hospitals from the area, and the school became 'scientized' by the creation of new academic departments and the introduction of new technologies. A signal event at the hospital that took place, like Bannister's mile, 50 years ago was Felix Eastcott's pioneering carotid endarterectomy.

The main political consequence of the 'scientization' of St Mary's was to be seen during the deanship of Peter Richards (1979–1995)—an era in which nearly all the London teaching hospitals lost their independence. After much controversy, the school merged in 1988 with Imperial College, Richards having persuaded them of the school's high performance in research; indeed, he argued that, head for head, St Mary's outscored Imperial in Nobel Laureates and Fellows of the Royal Society. Elsbeth Heaman believes that Richards achieved 'minimal change with maximum protection'. Not everyone would agree wholeheartedly with this judgment.

Altogether, this History offers an enthralling story whose appeal extends far beyond the alumni of St Mary's and Imperial.