The fact that Mr. Rokesmith gives the book its title suggests that he is an important character. “Our mutual friend” as a phrase seems to suggest connections between people in different social circles, emphasizing the novel’s focus on how the fates of people from different parts of London are all connected. Mrs. Wilfer’s suspicions of the Boffins show her condescension toward them because of their lower-class background, even though Mrs. Wilfer herself is currently living in poverty.