A primary reason for increased government involvement in health care delivery resides in the acknowledged difficulty of the poor in obtaining adequate care. However, in the absence of knowledge about how health, health care, socio-economic status, race, ethnicity, and geographic location are related, policies aimed at implementing right to health care concepts threaten to squander resources without achieving any benefit for the poor. The approach taken here revolves around the specification of a model relating the health status of a population to its demand for care, and the various ways in which this demand can be satisfied or left unsatisfied. With the aid of the model, an attempt is made to differentiate between the medical professional's concept of need and the economist's concept of demand. This leads to examining the variables influencing the decisions of individuals to seek care, to accept care, and to follow through with care as well as the efficacy of care. Several research projects bearing on these relationships have been done. These include a model relating health status to demand for health care, analyses of urban physician office distribution, the efficacy of comprehensive care, the effects of air pollution and radiation on health, and the role of paramedics in the delivery of primary care. (Author/JM)