Reflections on the past and future of primary care.

Medical care and primary care were at one time synonymous. All health care was primary. The concept and terminology of primary care came into widespread use during the 1960s, reflecting a specific policy agenda: bolstering the role of the generalist physician, which had changed dramatically following World War II. This essay describes the transformation of the nineteenth-century physician making house calls on horseback into the twenty-first-century primary care physician contemplating the electronic records of her patient population. The essential point is that "primary care" was born out of tension with other forms of medical care. In the future, primary care will be reinvented, and changes will be caused by the sorts of external social, political, and economic forces that previously led to systemic transformation.