Gabriel John Utterson investigates strange occurrences between his old friend, Dr Henry Jekyll, and the evil Edward Hyde. After his researches he will get to an astonishing truth. This novella by Robert Louis Stevenson is frequently interpreted as an examination of the duality of human nature, usually expressed as an inner struggle between good and evil, with variations such as human versus animal, or civilization versus barbarism. The work is also commonly associated with the Victorian concern over the public and private division, the individual's sense of playing a part and the class division of London. In this respect, the book has also been noted as "one of the best guidebooks of the Victorian era" because of its piercing description of the fundamental dichotomy of the 19th century "outward respectability and inward lust", as this period had a tendency for social hypocrisy.