 At its core, public health is concerned with promoting and protecting the health of  populations,[1]  broadly understood. Promoting and protecting the health of populations often involves or requires coordinated action on the part of governments. In the United States, for example, the Centers for Disease Control and Prevention, the Food and Drug Administration, the Environmental Protection Agency and the Consumer Protection Agency are, at least in part, public health agencies. All nations and most states or provinces and municipalities have health departments whose functions include everything from the inspection of commercial food service to the collection and use of epidemiological data for population surveillance of disease. Collective action to promote and protect population health also occurs at the global level, as exemplified by the activities of the World Health Organization.