Joseph Murray PhD is a senior research associate and Wellcome Trust Research Career Development Fellow in the department of psychiatry at Cambridge University UK. His main research interests are in developmental criminology cross-national comparisons and crime and violence in low- and middle-income countries. He was awarded the University of Cambridge Manuel Lopez-Rey Graduate Prize in Criminology in 2002 the University of Cambridge Nigel Walker Prize for his PhD in 2007 a British Academy Postdoctoral Fellowship in 2006 a Darwin College Research Fellowship in 2007 and the Distinguished Young Scholar Award of the American Society of Criminology Division of Corrections and Sentencing in 2008. Catrien C. J. H. Bijleveld PhD studied psychology and criminal law at Leiden University Netherlands earning her degree in statistical analysis of categorical time series. After working as an assistant professor at Leiden University she moved to the WODC Research and Documentation Center of the Netherlands Ministry of Justice. In 2001 she moved to NSCR in Leiden and became professor of criminological research methods at the VU University in Amsterdam. Her main research interests are in the areas of criminal careers female offenders the intergenerational transmission of offenders genocide and sex offending. She is the author of several textbooks and the editor of other volumes on crime and justice in the Netherlands and on the association between employment and offending. David P. Farrington OBE is professor emeritus of psychological criminology and Leverhulme Trust Emeritus Fellow at the Institute of Criminology at Cambridge University. He received the Stockholm Prize in Criminology in 2013. His major research interest is in developmental criminology and he is director of the Cambridge Study in Delinquent Development which is a prospective longitudinal survey of over 400 London males from age 8 to 56. In addition to more than 600 published journal articles and book chapters on criminological and psychological topics he has published nearly 100 books monographs and government publications. Rolf Loeber PhD is professor of psychiatry psychology epidemiology at the University of Pittsburgh USA. He is director of the Life History Program and is principal investigator of two longitudinal studies the Pittsburgh Youth Study and the Pittsburgh Girls Study. He has published widely in the fields of juvenile antisocial behavior and delinquency substance use and mental health problems. He is an elected member of the Koninklijke Academie van Wetenschappen (Royal Academy of Sciences) in the Netherlands and the Royal Irish Academy in Ireland.