R. Karl Hanson, Ph.D., C.Psych., is one of the leading researchers in the field of risk assessment and treatment for individuals with a history of sexual offending. Originally trained as a clinical psychologist, he was a researcher and research manager in the area of corrections and crime policy for Public Safety Canada between 1991 and 2017. Dr. Hanson has published more than 175 articles, including several highly influential reviews. He is lead author of the most widely used measures for assessing the risk and needs of individuals with a history of sexual offending (Static-99R; Static-2002R; STABLE-2007). He has received career contribution awards from the Association for the Treatment of Sexual Abusers, Public Safety Canada, the International Association for the Treatment of Sexual Offenders, and the Criminal Justice Section of the Canadian Psychological Association. Based in Ottawa, Canada, he is now adjunct faculty in the psychology departments of Carleton University (Ottawa) and Ryerson University (Toronto), and President of the not-for-profit organization SAARNA (Society for the Advancement of Actuarial Risk Need Assessment).