How does The Strange Case of Dr. Jekyll and Mr. Hyde combine a thriller with a moral allegory?

Robert Louis Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde functions as both a gripping thriller and a profound moral allegory by exploring the duality of human nature.

As a thriller, the narrative follows a mystery-driven structure. Told largely through the perspective of the lawyer Mr. Gabriel John Utterson, the plot unfolds as a series of investigations into the violent actions of the loathsome Mr. Hyde and his inexplicable connection to the respected Dr. Henry Jekyll. The suspense builds through the discovery of strange wills, witness accounts of brutality, and the eventual revelation of Jekyll’s secret laboratory experiments.1

As a moral allegory, the novella serves as a critique of the Victorian era’s "bifurcated self." Jekyll represents the outward gentility and rational public persona, while Hyde embodies the repressed, baser desires lurking beneath the surface. By physically separating these aspects through a potion, Stevenson illustrates the struggle between good and evil. The fact that Hyde is smaller than Jekyll suggests that evil may be a smaller portion of the human personality, yet one capable of forceful, violent expression when unleashed.1