How do you go from being one of several children of wealthy, celebrity parents to, as Dr. Jim Yong Kim, the president of Dartmouth College, has called her, "one of the great human beings walking the earth right now"? Ophelia Dahl traveled from Buckinghamshire to Haiti in 1983 and fell in love with the country and with Paul Farmer, a recent graduate of Duke who would become a famous doctor. With others they founded Partners in Health, the...