Stevenson was nine-years-old when Charles Darwin published The Origin of Species, the book that introduced his Theory of Evolution to the public. Darwin's theory influenced Stevenson's creation of Dr. Jekyll as a character..... a man who was meddling in matters which only God had control over. Jekyll's transformation to the ape-like Hyde links Darwin's idea of the primitive nature inside us. At the time the book was published, the public viewed science as being in opposition to religion. As a result, most people thought they had to choose one or the other. Stevenson's main character supported those fears.