Definitions of health have evolved over the course of this century from the simple absence of diagnosable disease, to a state of well-being to the inclusion of the capacity to live and work in community.

Public health moves the concept of health into the realm of a shared concern, whatever definition of health is understood. While public health can be and is pursued by all sectors of the community in some way, the definition implies that there is an organized and explicit commitment to bring about the desired conditions. Such a commitment is generally acted upon at least in part through governmental action.