Professor John Deanfield is Professor of Cardiology at the Institute of Child Health, University College London. He has been instrumental in the successful development of a new area of medical care and clinical research - the adolescent and grown-up with congenital heart disease. He has contributed extensively to our knowledge of the late haemodynamic and electrophysiological consequences of congenital heart disease and on the psychological, social and cognitive consequences of cardiac surgery in childhood. He has also made major contributions to studies of the childhood origins of atherosclerosis and has developed methods for the non-invasive detection and assessment of risk for atherosclerosis.