A London lawyer named Gabriel John Utterson investigates strange occurrences between his old friend, Dr. Henry Jekyll, and the evil Edward Hyde.
Then he realizes, that Henry Jekyll and Edward Hyde are two personalities within Dr. Jekyll, one apparently good and the other evil.
"The Strange Case of Dr. Jekyll and Mr. Hyde" is the original title of a novel by the Scottish author Robert Louis Stevenson, that was first published in 1886.
Written in the rigid and strict Victorean Era it anticipates modern psychology.