This report reviews approaches that federal, state, and local governments have used to integrate the delivery of health and other educational and social services to at-risk families, and examines barriers to designing and implementing integrated service delivery systems. The report contrasts "system-oriented" integration efforts, which create new systems that would deliver services more comprehensively, and "service-oriented" efforts, which link clients to existing services and unite various service providers. Two federal programs are reviewed--Project Head Start and Part H of the Individuals with Disabilities Education Act--along with a state-private child welfare initiative supported by the Annie E. Casey Foundation. The Part H and the state-level Annie Casey initiatives illustrate the system-oriented approach, while Head Start and the local-level service delivery components of the Annie Casey initiatives represent the service-oriented approach. The report concludes that service-oriented initiatives have been more successful, and urges that Congress be cautious in considering initiatives that call for state and local governments to make fundamental changes in service delivery systems, because the obstacles and risks of failure are great. Appendixes describe past federal efforts to integrate services and describe the service integration programs which were examined for this report. (JDD)