The current status of preventive intervention programs designed to reduce the school readiness gap for young children at environmental risk is examined in the context of developmental science. A review of program effectiveness suggests that future progress in this area should be grounded in a knowledge base that adopts the framework of developmental science and establishes unambiguous goals and implementation strategies as a foundation for program development. The Developmental Systems Approach is suggested as such a model, as it is consistent with developmental and existing intervention science, and it emphasizes program continuity, relationships, and comprehensiveness. A long-term plan for community-based systems development is presented. (author abstract)