John F. MacLeod, currently a Visiting Scholar at the Institute of Criminology, Cambridge University, retired in 2007 from a long career as a government scientist. Whilst working for the Home Office he conducted research, analysis and modelling in support of criminal justice policy, with a particular interest in criminal careers.
Peter G. Grove previously worked for Home Office on a number of areas of quantitative criminology. This included acting as statistical advisor for the national evaluation of the effectiveness of CCTV and the British Crime Survey. In collaboration with John Macleod, he constructed a quantitative predictive theory of offending behaviour.
David P. Farrington, OBE, is Professor of Psychological Criminology at the Institute of Criminology, Cambridge University. 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 age 48.