The field of population health includes examination of the distribution of health outcomes within a population, the social and economic determinants of those distributions, and the range of policies and interventions that bridge the two. The field is necessarily multi-disciplinary and typically addresses problems of disease causation and prevention, the multiple determinants of population health, optimal health care delivery, and allocation of health care resources. This five year research and outreach initiative is intended to improve public policy and practice and to improve teaching in population health. It will generate 10-40 or more case studies of innovative and successful population health initiatives to inform policy and serve as teaching cases.