One of the striking characteristics of twentieth century medicine was its domination by Anglo-Saxon attitudes and ideas—sustained by the close, almost symbiotic, ties between leading researchers in Britain and the United States. That relationship may be more one-sided than it once was, but it is still heartening to reflect just how many of the important innovations originated from British shores—including antibiotics, of course, but also intraocular implants, hip replacements, CT scanners, in-vitro fertilization, Sir James Black's pharmaceutical discoveries and much else besides. The transatlantic medical shuffle between the two countries stretches back a long way—Sir William Osler's translation from Johns Hopkins to Oxford being an obvious example—but probably the most significant event was the flood of young American research-oriented doctors who arrived in Britain in 1917 soon after the United States entered the First World War. Charles Woolley, Emeritus Professor of Medicine at Ohio State University, locates the origins of what would prove to be the very fruitful Anglo-American cooperation in cardiology to a truly remarkable coming together of doctors from the two countries at the 700-bedded Military Heart Hospital in Colchester. The US medical officers posted to the hospital—all of whom subsequently would become leaders in their field—included Samuel Levine, Marcus Rothschild and Frank Wilson while the British consulting staff included (amazingly) Sir William Osler, Sir James Mackenzie, John Parkinson, Sir Clifford Allbutt and Thomas Lewis. It is difficult to imagine a more distinguished roll call or a more stimulating environment, heightened by the intellectual challenge posed by the condition for which the hospital had been established—the enigma of ‘soldier's heart’. Fifty years earlier Jacob da Costa had described a syndrome of pain, palpitations, shortness of breath and tachycardia in combatants of the American Civil War, and now thousands of soldiers were being invalided out of the trenches in Northern France with precisely the same symtomatology. But was this an organic disease—as Sir Clifford Allbutt maintained—whose unique pattern of symptoms and frequently noted regurgitant murmurs seemed characteristic of diseased heart muscle? Or was it, as Thomas Lewis maintained, a functional disorder—an ‘effort’ syndrome mimicking the typical features of excess effort in men while they were still at rest. The resolution of this clinical conundrum was obviously highly relevant in deciding whether the invalided soldiers should be discharged on the grounds of incapacity for duty. But it also touched on the whole spectrum of recent physiological investigations into the control of the heartbeat and cardiac muscle contractility. Soldier's heart was, in short, a big issue and a testing ground for the scientific credentials of the nascent discipline of cardiology. And if that were not enough to make Charles Woolley's account worth reading, he has been helped vastly by one of those all too rare jewels of medical history—a contemporaneous account of the personalities and events at the military hospital as recorded in Samuel Levine's wartime diaries. Levine is both an astute observer and an elegant stylist, so his portraits of Osler, Mackenzie, Lewis and his fellow American medical officers are of immense value. Particularly memorable is his account of Sir William Osler's brilliant and sympathetic display of clinical skills at the bedside just a few days after his beloved and only son Revere had been killed in action at the front. Woolley's book might have been better organized and would have benefited from a wider perspective to include the experience of those afflicted by soldier's heart—but there is so much else going for it these are mere quibbles. It concludes with a retrospective verdict on the conflicting views over the aetiology of soldier's heart, which is particularly relevant in this age of Gulf War syndrome and chronic fatigue.