Age: 50
Occupation: Chairman of Harvard Medical School's Department of Global Health and Social Medicine
Previous TIME 100 Appearances: 0
Perhaps it's appropriate that Farmer's pioneering career to bring health care to the developing world began in Haiti in 1987, when a group he co-founded, Partners in Health, launched a hospital in Cange. These days the anthropologist–physician lives in Kigali, Rwanda, and oversees projects in that country as well as in Russia, Lesotho, Malawi and Peru. But when the massive earthquake struck in Haiti, he knew he had to act. He's now former President Bill Clinton's right-hand man as a U.S. deputy special envoy to Haiti, helping rebuild the country's crippled health infrastructure (most hospitals in Port-au-Prince collapsed in the disaster).