Howard Barbaree, PhD, is currently Head of Impulse Control Disorders Programme at the Clark Institute of Psychiatry in Toronto, Canada. For the past 13 years, he has been a Professor in Psychology at Queen's University, during which time he has devoted most of his professional work to research, teaching, and clinical practice related to sexual aggression and sexual deviance. Dr. Barbaree has published numerous journal articals and book chapters on the topic, and he is co-editor of theHandbook of Sexual Assault: Issues, Theories, and Treatment of the Offender(Plenum Publishing Corp.). He is the founding director of the Warkworth Sexual Behavior Clinic, a Canadian Federal Penitentiary treatment program for sexual offenders. Dr. Barbaree was born and educated in British Columbia, Canada, and received his PhD in Psychology from Queen's University in 1974. William Marshall, PhD, is a Professor of Psychology at Queen's University, Kingston, Canada. He has devoted the past 23 years to research and clinical aspects of the assessment and treatment of the sex offender. He has published extensively, with over 100 journal articles and book chapters to his credit. He is a co-editor of theHandbook of Sexual Assault: Issues, Theories, and Treatment of the Offender(Plenum Publishing Corp.)., and co-author ofCriminal Neglect: Why Sex Offenders Go Free(Doubleday). Dr. Marshall is the founding Director of the Kingstom Sexual Behavior Clinic, a community-based assessment and treatment program for adult and adolescent sex offenders. In addition, he has assisted in the establishment of sex offender treatment programs in six different countires throughout the world. Dr. Marshall was born in Australis, educated in England, and received his PhD from Queen's University in 1971.