In this fascinating book, Reid examines Robert Louis Stevenson's writings in the context of late-Victorian evolutionist thought, arguing that an interest in 'primitive' life is at the heart of his work. She investigates a wide range of Stevenson's writings, including Dr Jekyll and Mr Hyde and Treasure Island as well as previously unpublished material from the Stevenson archive at Yale University. Reid offers a new way of understanding the relationship between his Scottish and Polynesian work, showing how an ambivalent engagement with psychological and anthropological debates unites his oeuvre. She also illuminates the creative intersections between late-Victorian literary and scientific discourses, and demonstrates that Stevenson dealt critically and dynamically with evolutionist thought. Unsettling evolutionist assumptions about the inevitable progress from 'savagery' to 'civilization', his works explore and celebrate the enduring heritage of 'primitive' instincts in modern life.