Setting: The story takes place of Victorian England as shown in "... led them down a bystreet in a busy quarter of London" (Stevenson 11). There also numerous other mentions of London and often mentions of the year 18-- which signifies that everyone knew the current year. The setting helps establish a sense of what the times would've been like as compared to now. The time period is a sign of how archaic their sciences were so it gives reason for the extremely disturbing ending of the strange potion.
Characterization: The characters in this novel help to create a believable story in their situations. Having great desire for a pleasnt public image, this drives Dr. Jekyll to separate his malevolent and pure natures so that he could act in devious ways and not feel the regret of his actions because that was a completely different person. Having Utterson be a lawyer gives great reason that his inner feelings are always to be respectable and do what is needed if he feels it is something he is obligated to do.
Metaphors/Allegory: Metaphors in this story are often used in the similarites of Jekyll and Hyde and are mostly about them. One is that Hyde is a smaller, ugly man which is used to represent his awful nature and that he is formed purely from Jekyll's not-so-nice feelings. These metaphors help point out a charcter's feelings and are used sparingly to increase their effect.
Point of View: We get to see Utterson's point of view for almost all of the story. This helps create the sense of mystery as we can only learn whatever Utterson learns throughout the novel. Utterson helps to build a very real world through his thoughts and responses to the events of the story.
Mood and Tone: This story builds a very mysterious feeling throughout the book. In its use of letters of secrecy from other characters we can only know what Utterson learns. Occurences such as Jekyll's quick disappearance from his window after talking to friends make the reader think they know what has happened but we can't truly find out until the end of the novel in the resolution. Having this resolution at the end also ties up any loose ends in the story which gives a sense of whether or not your guesses were right. Whether its where has Hyde gone or what are they using these materials for this novel keeps the reader guessing.
Theme: One of the themes in this novel is that trusting your friends can often lead to good things. While the end result of Utterson learning about Hyde and and Jekyll is not so good, Utterson followed the words of his colleague and it turned out okay for him. He solved the case of Jekyll and Hyde and learned what he wanted to through his compliance with the letters. Another theme is that letting the bad thoughts turn into actions never ends in good situations. Jekyll thought it was healthy to let out his despicable side and it eventually overcame him. Allowing this side to be out and about only made it harder to contain it later.