In recent years several scholarly reviews of the prevention literature have concluded that there are a number of targeted intervention strategies that do produce consistent positive effects in reducing future delinquency (McGill, Mihalic, and Grotpeter 1997; Greenwood et al. 1996; Karoly et al. 1998; Bayley 1998). Not only do these programs reduce the amount of future crimes committed by high-risk youth, but they can also save government, as well as potential crime victims, substantial sums of money Policymakers interested in maximizing the effectiveness of their investments in fighting crime need to consider the cost-effectiveness of appropriate early interventions compared to additional expenditures on police, courts, jails, and prisons. In this chapter we show how some publicly funded early interventions may actually yield monetary returns in excess of their costs. 1