•Why it earns a slot
Stevenson's novella gave the English language the phrase 'Jekyll and Hyde' and remains the definitive literary treatment of psychological duality, presenting its horror not through the supernatural but through a scientist's rational attempt to resolve the moral contradictions within himself.
London lawyer Mr. Utterson grows alarmed by his friend Dr. Henry Jekyll's mysterious connection to the brutal, universally repellent Edward Hyde. The truth, revealed in final confessions, is that Jekyll chemically separated his own dual nature, creating Hyde as the pure embodiment of his evil side, only to lose control as Hyde grew dominant and the transformations became involuntary. Trapped and unable to obtain the original drug formula, Jekyll writes his confession and dies as Hyde, who takes poison rather than face the gallows.
This distillation is written from the freely available original, which is always the better read when you have the time: gutenberg.org.