Amanda E. Perry is a forensic psychologist working as a research fellow for the Centre for Criminal Justice Economics and Psychology at the University of York. Amanda has worked in academia, healthcare and forensic settings. Her specialist areas of interest are; systematic review and evaluation of research methodology, Screening and assessment for suicide and self-harm risk in offenders, and mental-health services. She has published systematic reviews for the Cochrane and Campbell collaborations on drug treatment for offenders and the effectiveness of screening and assessment tools for offenders, and is a guest lecturer for the MSc in Applied Forensic Psychology course at the University of York. Cynthia McDougall, OBE, is professor and Director of the MSC in Applied Forensic Psychology at the University of York, and co-director of the university's Centre for Criminal Justice Economics and Psychology. She has wide practical and research experience in crime-related issues, having worked as a probation officer in the community and as a psychologist in prisons, as head of psychology for prison and probations services. She is a chartered forensic psychologist, a consultant Psychologist to the Durham probation area and a member of HM Prison Service Close Supervision Centres Advisory Group. David P. Farrington, OBE, is professor of psychological criminology at the Institute of Criminology, Cambridge University. He is also co-chair of the Campbell Collaboration Crime and Justice Group, a member of the board of directors of the International Society of Criminology, and joint editor of Cambridge Studies in Criminology and the journal Criminal Behaviour and Mental Health. His major research interest is in the longitudinal survey of delinquency and crime, and he is director of the Cambridge Study in Delinquent Development, a prospective longitudinal survey of more than 400 London males between the ages of 8 and 48. In addition to more than 360 published papers on criminological and psychological topics, he has published 41 books, monographs and government publications, one of which ( Understanding and Controlling Crime, 1986) won the prize of distinguished scholarship of the American Sociological Association criminology section.