One of the hallmarks of the Victorian literary achievement is genius wedded to industry and professionalism. One has only to think of Dickens and Trollope or George Eliot and Matthew Arnold to recall the persistence, self-discipline, and patiently sustained labor that resulted in the steady accumulation of a body of works as firm and fixed as the building blocks of a great edifice. It is one of the many paradoxes in the life of Robert Louis Stevenson that, though he was a worker and craftsman of extraordinary skill, his literary image is that of a whimsical amateur, an aesthetic drifter. Not only did he move from place to place, scribbling on trains, dictating in bed, but he seems to have written a bit of everything.

In fact, though Stevenson wrote poetry, essays, travel books, hundreds of wonderful letters, and a few plays, his reputation as an author writing...