As early as the 1920s, and subsequently in the 1959 Build and Blood Pressure Study (S1. 5-1) of almost 5 million adults insured between 1934 and 1954, a strong direct relationship was noted between level of BP and risk of clinical complications and death. In the 1960s, these findings were confirmed in a series of reports from the Framingham Heart Study (S1. 5-2). The 1967 and 1970 Veterans Administration Cooperative Study Group reports ushered in the era of effective treatment for high BP (S1. 5-3, S1. 5-4). The first comprehensive guideline for detection, evaluation, and management of high BP was published in 1977, under the sponsorship of the NHLBI (S1. 5-5). In subsequent years, a series of Joint National Committee (JNC) BP guidelines were published to assist the practice community and improve prevention, awareness, treatment, and control of high BP (S1. 5-5—S1. 5-7). The present guideline updates prior JNC reports.