Jekyll's alter ego is Hyde, a four-letter word. Dr. Jekyll and Mr. Hyde is a novella written by Robert Louis Stevenson in 1886. It tells the story of a London lawyer named Gabriel John Utterson who investigates strange occurrences between his old friend, Dr. Henry Jekyll, and the evil Edward Hyde. Jekyll is a kind and respected doctor, while Hyde is a depraved and violent man. The two are revealed to be the same person, with Jekyll having created a potion that allows him to transform into Hyde.