Clarendon Studies in Criminology aims to provide a forum for outstanding empirical and theoretical work in all aspects of criminology and criminal justice, broadly understood. The Editors welcome submissions from established scholars, as well as excellent PhD work. The Series was inaugurated in 1994, with Roger Hood as its fi rst General Editor, following discussions between Oxford University Press and three criminology centres. It is edited under the auspices of these three centres: the Cambridge Institute of Criminology, the Mannheim Centre for Criminology at the London School of Economics, and the Centre for Criminology at the University of Oxford. Each supplies members of the Editorial Board and, in turn, the Series Editor. This book addresses an important, central area of criminological enquiry—namely, the theory of criminal careers. Two of the authors—John F. MacLeod and Peter G. Grove—are former scientifi c researchers who undertook important criminal career research at the Home Offi ce in the fi rst years of this century and the third— David P. Farrington—has a very long and distinguished history of path-breaking and sophisticated research in the fi eld. Drawing upon their combined expertise, which includes psychology, statistics, and mathematical modelling, the present volume examines the validity of existing criminal career theories and proposes a theory and consequent mathematical models to explain offending, conviction, and reconviction.