Professor Gerry Stimson is a public health social scientist, with over 40 years’ experience of public health research and advocacy in the field of psychoactive substance use. He was one of the founders of harm reduction in the 1980s, and much of his academic research focused on reducing drug and alcohol related harms. He is Honorary Professor at the London School of Hygiene and Tropical Medicine, Emeritus Professor at Imperial College London, and the Editor of the International Journal of Drug Policy. He founded the Department of Social Science and Medicine at Imperial College. From 1990 to 2004, he was Director of the Centre for Research on Drugs and Health Behaviour. He was Executive Director of the International Harm Reduction Association from 2004 to 2010.