In recent years, responding to the evidence on the determinants of population health and to the broad strategic vision of health promotion, hospitals and other healthcare organizations have increasingly defined their mission as improving the health of the community or population that they serve. In the United States, the Healthcare Forum has stressed the important role that hospitals can play in creating healthier communities. In this and subsequent articles and related case studies in Hospital Quarterly, we will explore the role that healthcare organizations can play in achieving the goal of healthy people in healthy communities in a healthy world. But first it is important to discuss the philosophical and practical limitations to that role, in order to understand what healthcare organizations might really be able to contribute.