Just as the molecular and chemistry oriented sciences were adopted as the 20th century medical paradigm, incorporation of the patient's perspective into a relationship-centered medical paradigm has been suggested as appropriate for the 21st century. It is the medical dialogue that provides the fundamental vehicle through which the paradigmatic battle of perspectives is waged and the therapeutic relationship is defined. In many regards, the primary challenge to the field is the development of operationally defined and measurable indicators of medical communication that will provide a valid representation of the conceptual models of the therapeutic relationship. The purpose of this essay is to explore the implications of a relationship-centered medical paradigm on the nature of the patient-physician relationship and its expression in the communication of routine medical practice. An organizing framework for distinguishing commonly measured communication elements into conceptually distinct components is suggested. Application of this framework is illustrated through an empirical study of communication in primary care practice. The results of the study demonstrate the usefulness of this approach in linking communication to models of therapeutic relationships. The importance of medical communication is further explored in a summary of studies that establish its association to outcomes and in an overview of future challenges to the field.