This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables. IT IS GENERALLY RECOGNIZED that atherosclerosis is a complex disease of the arteries and that a number of factors influence its development. In particular, coronary atherosclerosis and the resultant heart disease have been the subject of many studies because of the high morbidity and mortality rates and because of the limitations of present-day therapy. Much evidence implicates diet as one of the key etiological factors. Within the last 10 years several investigators have undertaken studies to examine the influence of dietary modification on the occurrence of clinical coronary heart disease. By 1959 it was apparent that large-scale field trials might be feasible and that a national cooperative effort might be the appropriate means to accomplish this difficult research mission. In 1960, with the support of the National Heart Institute of the US Public Health Service, an Executive Committee on Diet and Heart Disease was established under the chairmanship of Dr.