Calvin M. Langton, PhD, CPsych, is a member of faculty at Ryerson University, Toronto, and an associate faculty member at the Ontario Institute for Studies in Education at the University of Toronto. He is also an honorary lecturer in the School of Community Health Sciences, University of Nottingham, United Kingdom, and a senior fellow at the Institute of Mental Health, Nottinghamshire Health Care Trust, United Kingdom. Dr. Langton is a registered psychologist in Ontario, and a chartered psychologist in the United Kingdom. He has a private clinical and forensic psychology practice that provides psychological services to adults, adolescents, children, and their families, and that specializes in the evaluation of individuals who have sexually offended. His primary research interests include assessment and treatment issues pertaining to sexual offending, psychopathy, and personality disorders. He serves on the editorial boards for Sexual Abuse: A Journal of Research and Treatment, Criminal Justice and Behavior, and the Journal of Forensic Psychiatry and Psychology.