The text used for this Norton Critical Edition of Stevenson's novella is that of the 1886 first edition, the only edition which was set directly from the author's manuscript. It has been rigorously annotated for undergraduate readers, and is accompanied by a textual appendix. The five critical essays centre on the novella's allegorical dimensions and its narrative technique. Four scientific essays, including one by Stephen Jay Gould, discuss the concept of the divided self, multiple personality disorders and the use of narcotics. A section on performance adaptations examines the many ways the plot has been dramatized over more than a century, as an outlet for modern psychological and social concerns.