How they've changed and how they're changing medicine.

Most Americans have, until recently favored a health care system preoccupied with treatment of disease, oriented around hospitals, and dominated by specialists. But this concept is being changed by economic, demographic, and technologic stresses. The public's new perception of how health care should be delivered is reflected by community-based medical services that emphasize health maintenance and that are dominated by primary physicians. It is not surprising that doctors are confused by this turn of events. Those who have built their careers around a particular set of concepts rarely find it easy to understand what is happening when the paradigm shifts. Nevertheless, understanding is essential if today's physicians--and tomorrow's--are to practice within the new health care system and continue to preserve medicine's professional values and traditions.