The life of Robert Louis Stevenson was regarded by his public, his friends, and his biographers to be as thrilling as the adventures in the stories he wrote. He was born in Scotland on 13 November 1850 to a respectable, middle-class family. His father, Thomas Stevenson, a lighthouse engineer and a devout Presbyterian, brought up his son according to the strict principles of mid-Victorian Edinburgh. From his mother, Margaret, Stevenson inherited an optimistic attitude toward life as well as a susceptibility to tuberculosis that kept mother and son in lifelong states of ill health. His early childhood was lonely, dominated by severe bouts of sickness that left him bedridden for weeks at a time. He was devotedly cared for by his mother and by his nanny Alison Cunningham. "Cummy," as he nicknamed his nurse, would read to Stevenson from the Old Testament, from John Bunyan's The Pilgrim's Progress (1678), and from...