BACKGROUND: In taking the pulse of global health in 1974, WHO member states concluded that despite vaccines, antibiotic drugs, and a host of extraordinary advances in medical technology, the world was far from healthy. There was a "signal failure," the 27th World Health Assembly concluded, to provide basic services to two-thirds of the world's population, particularly to rural inhabitants and the urban poor, who, despite being the most needy and in the majority, were the most neglected. That assessment—made 24 years after WHO's establishment—led to a reorientation of WHO's outlook and to the adoption of the goal of "health for all by the year 2000" through the approach of primary health care. Although WHO's great achievement remained the eradication of smallpox, the HIV/AIDS pandemic and a virulent resurgence of preventable diseases like malaria and tuberculosis posed grave challenges to the goal of "health for all" as the 21st century dawned. The main task of WHO since its founding has been to work to ensure that people everywhere have access to health services that will enable them to lead socially and economically productive lives.