Coronary atherosclerosis is the leading cause of death in this country and the developed countries of the world. Although modern coronary care units have resulted in a markedly decreased hospital mortality from acute myocardial infarction, especially in those patients who enter the hospital early, its overall impact is limited since two-thirds of patients who die from coronary disease do not reach the hospital. When the trial was initiated in 1979, new approaches to the medical treatment of coronary disease and its complications were needed with an effort directed towards prevention of its progression and prevention of its complications through medical therapy. This prevention could save significant health care dollars over the long-term especially if the need for aortocoronary bypass graft surgery and the incidence of myocardial infarction could be reduced. Early identification of the patient at risk of developing coronary disease or of those with early coronary artery lesions would allow a greater impact of any successful intervention therapy.