The faithful transcription of dreams has always played a major role in Dali's paintings. The painter had studied psycho-analysis and the works of Freud before joining the Surrealists. To dream is easy for him because of his Mediterranean heritage. A siesta, to him, has always opened the doors of a pre-sleep period, the instant when one forget the presence of one's body. Dali's demonology owes a great deal to his reveries. They have given birth to heterogeneous elements which he then brings together in his paintings without always knowing why. In the works of the Surrealist period, Dali treated those elements of disparate appearance with absolute realism which emphasized the proper character of each one of them, making an exact copy from a document, a photograph, or the actual object, as well as using collage.