Ian Roberts is Professor of Epidemiology & Public Heath and co-director of the Clinical Trials Unit at the London School of Hygiene & Tropical Medicine. His main research interests are improving emergency care and the links between energy and health. He trained as a paediatrician and then in epidemiology at the University of Auckland, New Zealand and at McGill University, Canada. He established and is co-ordinating editor of the Cochrane Injuries Group, an international network of individuals that prepares and maintains systematic reviews of the effectiveness of interventions in the prevention, treatment and rehabilitation of injury. He is principal investigator of the CRASH trials, large international randomised controlled trials that seek better ways to treat seriously injured trauma patients. The MRC CRASH trial, which included 10,000 pateints with head injury from around the world, showed that corticosteroids, which were widely used in the management of head injury, did not improve patient outcome after head injury but increased the risk of death. The CRASH-2 trial has shown that tranexamic acid, an inexpensive and widely practicable treatment, safely reduces mortality in bleeding trauma patients. He is the author with Phil Edwards of The Energy Glut: the politics of fatness in an overheating world.