This chapter focuses on contemporary theoretical and research developments in the search for developmental patterns and age-linked correlates and causes of antisocial behaviours. The fundamental challenge in the search for the correlates and causation of antisocial behaviours arises from the complexity of human behaviour. Cross-sectional studies collecting data on separate cohorts differing in age provide some important clues about factors associated with antisocial behaviours at different stages of the development. The preferred design involves prospective longitudinal designs. In this the same individuals are followed over a period of time, changes in their behaviours are tracked, and factors associated with those changes are explored. The chapter discusses the advantages associated with this design. A growing body of cross-sectional and longitudinal research is now available on age-related risk factors associated with antisocial behaviours. This information helps assessing risk for antisocial behaviour at various developmental stages and developing prevention and intervention programmes.