This study presents a new approach to developing a typology of criminal activity. The distinguishing feature of the analysis is that it concentrates on determining types of activity rather than the amounts of activity over the life course. The methodology involves investigating criminal activity in a succession of five-year periods rather than the conventional approach of summarizing a ‘lifetime’ of crime. This provides scope for assessing changes and pathways of criminal activity as offenders grow older, and gives new insight into the concepts of specialization and versatility. The Home Office Offenders Index birth cohort for 1953 provided official conviction histories up to 1993 (age 40), and latent class analysis identified a fixed number of types of criminal behaviour separately for males and females. The patterns of offending varied markedly between males and females. Male offending (with nine identified types) showed greater diversity than female offending (with three identified types). For the males, each type of offending had a distinct age profile, but this was not evident with the females. A new definition of offending specialization is given, and is shown to increase for males as offenders grow older. A case study on one of the male offending types illustrates the potential for identifying pathways of crime.