To conduct a prospective observational study of the characteristics of subclinical cardiovascular disease (disease detected non-invasively before it has produced signs and symptoms) that predict progression to clinically overt cardiovascular disease in a diverse and representative population-based sample of men and women aged 35-84. Specifically the study shall: determine characteristics related to progression of subclinical to clinical cardiovascular disease; identify factors related to newer measures of subclinical disease and examine relationship of new to established measures; and develop population-based methods, suitable for application in future screening and intervention studies, for identifying asymptomatic persons at highest risk of clinical events.