In the largely successful preventive approach to reduction in cardiovascular disease prevalence, three classic stages of investigation were used. First, an hypothesis was raised that diet and cholesterol levels were a cause of heart disease. Second, multiple longitudinal observational studies, led by the Framingham group, documented a strong association between these health risks and heart disease mortality. Finally, randomized controlled trials of cholesterol-lowering drugs established proof of causality. Our understanding of the Successful Aging phenomenon has followed the same sequence. The Compression of Morbidity hypothesis sets forth a new and promising paradigm. Multiple longitudinal and cross-sectional observational studies show strong associations consistent with the hypothesis. Finally, randomized controlled trials of healthy aging interventions prove our ability to successfully intervene in this most important of all contemporary health problems: the health of seniors [28].