Rory Collins is professor of Medicine & Epidemiology in Oxford. Clinical trials are an essential part of modern medical research, and Rory Collins is one of the best clinical trialist in the world today. Rory Collins has developed theoretical and practical aspects of “mega-trials”, and has selected questions of major clinical importance to be addressed by such studies. In cardiology his ISIS-2 trial showed that prompt treatment of heart attack with aspirin and fibrinolytics halves death rate. This trial has had a major influence on clinical practice throughout the world. More recently, his Heart Protection Study showed, that even for people with below-average blood cholesterol, a substantial further cholesterol reduction protects against heart attack and stroke. This again will save many lives. To design, conduct and report such large-scale trials, each involving a few tens of thousands of patients and hundreds of scientific and medical collaborators, and to complete each one within a reasonable timescale and at an affordable cost requires research leadership and scientific excellence of the highest order.