How and why do we measure blood pressure (BP)? Does it matter? How do we decide if BP is too high (a condition known as hypertension) and whether that is a result of aging, bad luck, or a disease? If it’s a disease, when and how should we treat it? How does hypertension interact with other diseases, and does race or ethnicity increase (or decrease) the risks of high BP? This presentation will provide a brief history of our developing understanding of hypertension’s central role in cardiovascular disease, kidney disease, and stroke. In particular, it will include a selective review of the research results which have driven diagnostic and treatment guidelines and public health policies over the past century.