Professor Michael Farrell is a psychiatrist and formerly at the National Addiction Centre, Institute of Psychiatry, King’s College, London. Currently, he is the Director of the National Drug and Alcohol Research Centre, University of NSW. His extensive research interests include treatment evaluation, including the development of the National Treatment Outcomes Profile, a brief outcomes measurement instrument for drug and alcohol dependence. He has a long standing interest in drug dependence in prisons and within the wider criminal justice system. He has been a member of the WHO Expert Committee on Drug and Alcohol Dependence since 1995.