FOR MANY YEARS atherosclerosis and diseases related to it were considered the inevitable result of the" aging process." Those seeking to discover possible causes of atherosclerotic disease were considered members of Mencken's" Cult of Hope," striving to find solutions to insoluble problems. In spite of the pessimism surrounding atherosclerotic disease, an increasing number of intensive investigations involving clinical, laboratory, and epidemiological research have greatly advanced our understanding of the nature of this disease and its determinants. Through epidemiological studies in particular, much has been learned concerning the circum-stances under which coronary heart disease arises and flourishes. Such studies have also provided a basis for thedevelopment of preventive programs in coronary heart disease, the major adult health problem in the United States.