Sometimes the very talented writer is able to introduce a central character that the readers never are allowed to meet. This character effects the actions of other characters, the plot of the novel and so forth but is never actually in the story. Maman, Meursault's mother, is the "invisible" character Camus created for The Stranger. She is the sole force driving the novel. Without her we would be unable to fully understand Meursault's character or the society he lives in. She drives the plot forward and propels our main character through conflicts. Maman's own death, which begins the book, ends up being the very reason for her son's death. Without Maman this would be a standard plot driven novel about a man who commits murder instead of an allusion to the world's reaction to existentialism.
"Maman died today. Or yesterday maybe, I don't know. I got a telegram from the home: 'Mother deceased. Funeral tomorrow. Faithfully yours.' That doesn't mean anything. Maybe it was yesterday."
Those are the opening lines of The Stranger. The first chapter covers the funeral where we first meet Meursault. Maman helps develop Meursualt's character in different ways. In this chapter he talks about the death of Maman and also copes with the loss internally. Generally we expect people to cry and feel immense grief when they lose a parent or anyone close to them for that matter. The fact that he does not show either of those things is the first clue to how unique Meursault's personality is in this society. He also doesn't know how old she was. The way he speaks of his mother in this paragraph gives a hint to his general detachment; to his tendency towards existential beliefs.
The day after the funeral Meursault spends time with an old co-worker, Marie. When he tells her that Maman was buried yesterday he has the desire to tell her it wasn't his ...