Dr. Henry Jekyll, nicknamed in some copies of the story as Harry Jekyll, and his alternative personality,
Mr. Edward Hyde, is the central character of Robert Louis Stevenson's 1886 novella
Strange Case of Dr Jekyll and Mr Hyde. In the story, he is a good friend of main protagonist Gabriel John Utterson. Jekyll is a kind and respected English doctor who has repressed evil urges inside of him. In an attempt to hide this, he develops a type of serum that he believes will effectively mask his dark side. Instead, Jekyll transforms into Edward Hyde, the physical and mental manifestation of his evil personality. This process happens more regularly until Jekyll becomes unable to control when the transformations occur.