In Dr Jekyll and Mr Hyde, Stevenson writes in the novel form. He uses features of the Gothic genre, which originated in the 18th century and describes an atmosphere which is sinister, grotesque or mysterious.
Gothic novels are often set in dark, mysterious places or ruined buildings. Stevenson's London, with its dark streets and ever-present fog fits the Gothic genre perfectly.
Stevenson also uses first person perspective which gives the reader great insight into the character's viewpoint. In this novel the reader is given the perspective of three different characters: Utterson, Dr Lanyon, and Dr Jekyll.