[Toward an operational definition of the health-illness process].

The article reviews the meaning of the terms health and illness, and seeks to define those aspects of these concepts that are most related to the supply of health services. After considering the process of health and illness and its implications for the the planning of health care, the authors express the need for conceptual models of health and environment (physical and social) that can be related to the objectives of the health system. As a part of the search for a better population data base, certain health and welfare indicators are suggested. The discussion concludes with a brief strategy for the operationalization of the health/illness continuum as a part of the planning for a national health service.