The Strange Case of Dr. Jekyll and Mr. Hyde In our world everyone has both a good side and a bad side to his character. If you are of weak mental ability, the evil side can take over and destroy you. In Robert Louis Stevenson's The Strange Case of DR. Jekyll and Mr. Hyde, this aspect, that of identity and personality can be found. According to The American Heritage Dictionary, identity can be defined as "the collective aspect of the set of characteristics by which a thing is recognizable or known." In this book, Stevenson uses the characters of Dr. Jekyll and Mr. Hyde to portray ones own identity, that of the ac