The movement toward systematic, national health planning in the United States began approximately a century ago (particularly in regard to the control of epidemics, and sanitation problems in general). However the decades following World War II have seen a proliferation of legislation in this area--including the Hill-Burton Legislation, Regional Medical Programs, and Comprehensive Health Planning. The National Health Planning and Resources Development Act of 1974 represents the federal government's most ambitious effort, to date, to implement regional planning--within the context of a national health planning policy, and may one day prove to have been the harbinger of a national health service in the United States. Health planning efforts have been particularly hampered due to difficulties in obtaining valid and reliable data upon which to base decisions. While some movement has been made in this area, with commonly-accepted techniques being developed, there is much room for further development and refinement of health planning methodology. Health planning, therefore, remains a rather imperfect "art", raising as many questions as it attempts to answer, at this point in time.