The United States continues to experiment with health care delivery and financing innovations, but relatively little attention is given to the public health system and its capacity for improving health status in the U.S. population at large. The public health system operates as a multisector enterprise in which government agencies work in conjunction with private and voluntary organizations to identify health risks in the population and to mobilize community-wide actions that prevent and contain these risks. The Affordable Care Act and related health reform initiatives are generating new interest in the question of how best to expand and integrate public health approaches into the larger U.S. health system. The research articles featured in this issue of Health Services Research cluster around two broad topics: how public health agencies can deliver services efficiently and how public health agencies can interact productively with other elements of the health system. The results suggest promising avenues for aligning medical care and public health practices.