The story of 'Dr. Jekyll and Mr. Hyde' is set in Victorian London, a time characterized by strict social codes and rapid industrial growth. Stevenson wrote the novel partly as a response to the era's obsession with morality, respectability, and the duality of human nature. The city’s contrasting environments—high society and seedy neighborhoods—mirror the conflicting personalities within the characters. Jekyll, a respected doctor, invents a potion to separate his good and evil sides. The phrase 'dual nature' encapsulates the central theme, highlighting the internal struggle between morality and temptation. Stevenson was influenced by contemporary theories of psychology and the prevalent Gothic literary style. The quote 'Man is not truly one, but truly two' captures the essence of the novel's exploration of identity and morality.

In the novel, Stevenson employs vivid imagery and symbolism to emphasize the contrast between Jekyll and Hyde. The description of Hyde as a 'troglodyte' suggests primitiveness, while the use of the phrase 'respectable society' contrasts with Hyde's depravity. The language Stevenson uses creates a mood of tension and curiosity, especially through the phrase 'the duality of human nature.'

Stevenson’s writing often includes complex sentence structures and careful word choice. For example, the phrase 'the duality of human nature' uses alliteration to draw attention. The sentence 'Man is not truly one, but truly two' employs parallelism to emphasize the contrast.