The double theme in literature has always fascinated me because it is a common theme in everyone's daily life, but at the same time, it is so difficult to be expressed and represented concretely.
A novel, which we can talk about, is a novel of the nineteenth century called The Strange Case of Dr. Jekyll and Mister Hyde, written by Robert Louis Stevenson. It talks about a Doctor, whose name is Jekyll, who is a good man and is respected by everyone. But one day he drinks a potion and transforms into Mister Hyde, changing his physical appearance and becoming a horrible nocturnal murderer.
This work aims to demonstrate that in every man there is a good and a bad part, but not only because the two parts coexist and complement each other.