"Jekyll and Hyde" is a novella by Robert Louis Stevenson that explores the theme of duality, illustrating the conflict between good and evil within a single individual. The story follows Dr. Jekyll, a respected scientist, who creates a potion that transforms him into Mr. Hyde, a violent and immoral alter ego. This transformation symbolizes the struggle between the civilized self and the darker instincts that reside within everyone. The duality in the narrative raises questions about identity and morality, suggesting that every person has both a good and a bad side. As Jekyll becomes increasingly consumed by Hyde, the story highlights the dangers of repressing one's darker impulses and the consequences of losing control over one's dual nature.