This paper proposes a strategic federal investment of $3 billion in the relatively small number of social interventions (i.e., programs, practices, strategies) shown in scientifically-rigorous studies to produce sizeable, sustained improvement in the lives of children and youth. Careful analyses show that the benefits of these interventions in preventing major social problems would far exceed the investment under any reasonable assumptions. [Advocacy of this proposal is supported by grants from the MacArthur Foundation and the Jerry Lee Foundation.]