Intervention strategies targeting juvenile delinquency and other problems have generally focused on children early in life. This chapter discusses evidence for the greater effectiveness of interventions that focus on the timing and sustainability of actions in relation to an individual's developmental pathways, rather than at an arbitrarily fixed age. It distinguishes between early intervention and intervention early in the pathway. Family, child care provisions, preschools, schools, peer groups, vocational, further and higher education, community organisations and employment are seen as key sustaining systems through the life course, as loci for prevention and intervention measures and for maintaining the benefits of those measures. References are made to the Iowa Orphangae Study of Keels, the High/Scope Perry Preschool Project, and the Australian Temperament Project.