The incidence of angina pectoris associated with coronary artery disease is increasing. It probably will continue to increase if medical progress continues and greater numbers live to reach angina ages. Its control is beyond the horizon of preventive medicine, nor is it at all likely that drug treatment or surgical measures will prove more than useful adjuncts to treatment in more than a small fraction of cases. One is forced, then, to rely chiefly on the daily regimen in giving advice to this increasing number of patients. It seems to us that we have been hindered in efforts toward improving the effectiveness of these daily regimens by a general belief that fatalities in angina pectoris are essentially haphazard in their origin and that regimens are comparatively ineffective to control them. One factor that has contributed to this attitude is that only recently have physicians attained a clear clinical picture of