Tracy Kidder met Paul Farmer in 1994, when Kidder was working on a story about American soldiers who were helping Haiti reinstitute democratic rule. At first, Kidder was not that impressed with Farmer, but when they ran into each other again, on a plane back to Miami, they started talking in more depth, and Kidder became fascinated. At times, Kidder weaves a traditional third-person biography of Farmer, synthesizing their talks and emails with details from the many people who make up Farmer’s complex life. At other times, though, Kidder puts himself directly into the narrative, as he does most emphatically early and late in Mountains Beyond Mountains, when he walks many hours with Farmer to visit some of the rural poor. These were but the slowest of the travels the two men shared, for Kidder accompanied Farmer on many trips, both to international summits and into the field, going with him to Moscow, Siberia, Peru, Cuba, Paris, Mexico, Montreal, New York City, and Boston.

Prior to writing Mountains Beyond Mountains, which became a New York Times bestseller, Kidder had written a number of successful books. The Soul of a New Machine (1981) won a Pulitzer Prize and National Book Award, establishing Kidder’s reputation as a nonfiction author. He followed it with House (1985), Home Town (2000), and other books. Kidder’s Among Schoolchildren won the 1990 Robert F. Kennedy Award, given for literature that champions social justice and concern for the poor. Though The Soul of a New Machine is about the computer industry and House is about the construction of a single award-winning home, what unites them and Kidder’s other books is his dense research and literary, almost novelistic style.

Born in New York City in 1945, Kidder attended Harvard for his undergraduate work and Iowa for his master’s. Kidder served in Vietnam, where he earned a Bronze Star.

Farmer was born into a curious, quirky family on October 29, 1959, in North Adams, Massachusetts. Farmer’s father, Paul Sr. (called “the Warden” for his strictness), was restless and moved his family to Alabama in 1966. Later on, his father bought a bus, and after 1971, the family lived on it … until Paul Sr. bought a fifty-foot boat and moved his family on to that. Farmer and his five siblings were free to pursue their own interests (one of his brothers, for example, is a professional wrestler), and he became interested in science at an early age. Farmer had one serious relationship before marriage, to Ophelia Dahl, who helped found the organization Partners in Health. In 1996, Farmer married Didi Bertrand, a Haitian who was known as the “the most beautiful woman in Cange,” the region of Haiti where Farmer focused most of his work.

He attended Duke University, graduating summa cum laude in 1982. While he was attending Duke, Farmer began his world travels, spending two semesters in Paris and, most important of all, finding his purpose in life. His interest in science sharpened into an interest in medicine and, specifically, public health. At Duke, Farmer also met the poor migrant laborers who worked the North Carolina farms and the committed social activists who helped them. Among these workers were Haitians, and their particular plight fascinated Farmer, leading him to visit Haiti in 1983. While there, he worked for a series of health care organizations, moving from the relatively well-stocked medical facilities in urban environments to the poorer clinics that served more rural populations. In 1987, Farmer founded Partners in Health (PIH) with Thomas White and Todd McCormack. Partners in Health started in Haiti but eventually spawned branches in Peru,...