Hywel Williams is Foundation Professor of Dermato-Epidemiology at the University of Nottingham. He is recognized internationally for researching the causes and treatment of childhood eczema and his scientific contributions include diagnostic criteria that are now the most widely used worldwide and describing global patterns of eczema prevalence. He has led many systematic reviews in the area and numerous clinical trials. Hywel founded the Centre of Evidence-Based Dermatology at Nottingham, where he leads an NIHR Programme Grant and the UK Dermatology Clinical Trials Network. He became chair of the NIHR Health Technology Commissioning Board HTA deputy director in 2010.