Even though medicine is a social enterprise and is influenced by larger social (political, economic, cultural, and religious) values and goals, its central relationship is narrowly defined in terms of the patient-physician relationship. "The encounter between patient and physician," according to Earl Shelp, "may be characterized as the focus of medicine" (1983, p. vii). It is this relationship that is one of the most important elements in defining the very nature of medicine itself, since medicine is therapeutic at its core.In this chapter, defining the nature of medicine per se is not the focus-that is reserved for the concluding chapter-but rather the focus is on the various types of models proposed to account for the patient-physician or therapeutic relationship. The number of models seems endless and they range from the classic authoritarian models such as paternalism to the contemporary partnership models. Indeed, Danner Clouser (1983) bemoans the plethora of models but acknowledges that many more can be invented, such as the "bus driver" model or "pin-ball machine" model.