Stephen McMahon is Professor of Cardiovascular Medicine and Epidemiology at the University of Oxford. He has made major contributions to public health, both through his large-scale observational studies of the relevance of levels of blood pressure, lipids and glucose to the risk of vascular disease and by performing randomised trials demonstrating the impact that can be achieved by modifying levels of these risk factors. He established the George Institute for Global Health in Sydney and satellite centres in China, India and the UK which are assessing population-based health delivery approaches in developing countries. His work has prevented much premature death and disability worldwide.