What does the title refer to?
"The big sleep" is slang for death and the eternal afterlife. That euphemism is never directly explained in the film, leaving open what it means. In the novel by Raymond Chandler, Marlowe considers the "big sleep" in relation to Canino's death, and the fact that he has been drawn into the nastiness of corruption and crime—killing Marlowe—in order to stay alive. It is unclear to Marlowe whether life, with all its corruption and sin, is preferable to "the big sleep," in which one finally communes with peacefulness and silence.
What is gained and what is lost in the decision to tell the story from an objective perspective?
The objective narration adopted by the filmmakers to allow the audience to collect clues at the same time as Marlowe—but without insight into how he is putting those clues together—helps to build the suspense of the mystery as it plays out. By not knowing anything more than the detective, the audience feels as though they are working alongside Marlowe to resolve the mystery. At the same time, however, since we only know what Marlowe knows and not what he thinks, the audience is left with some unanswered questions, and at times the plot becomes almost prohibitively confusing. While Marlowe is an unusually gifted detective, able to piece together clues, the audience is working with fragments and speculation for most of the film. What results is a glorious and compelling mess, one which leaves the viewer scratching their head, but still relishing in the elegant style of Hawks' filmmaking and the many wonderful performances.
Why does Marlowe seem to respect Harry Jones?
While it remains consistently unclear whether Marlowe respects anyone (even himself), he exhibits a strange regard for the short gangster, Harry Jones. While all the other villains are nefarious, deceptive, and dishonest, Jones exhibits an unusual straightforwardness with Marlowe, which wins his affection. Additionally, Harry lies about Agnes's whereabouts to Canino in order to save Agnes, and then drinks the poison concoction that Canino gives him, dutifully. Marlowe respects the fact that Harry Jones sacrifices his own life for the sake of another, because he knows that that is what is right. Marlowe identifies with Harry Jones, because they both have to do bad things in order to do the right thing. Marlowe sees something of himself in the tragic plight of Jones.
What is the difference between Vivian and her sister Carmen?
The difference between the Sternwood sisters is perhaps best encapsulated in how they are described by their father General Sternwood. He says, "They're alike only in having the same corrupt blood. Vivian is spoilt, exacting, smart and ruthless. Carmen is still a little child who likes to pull the wings off flies." Sternwood describes them as very distinct from one another, though his terms are somewhat difficult to decipher. Vivian is too smart and bold for her own good, and we soon find out that, while elegant, she has a large appetite for gambling, an unseemly activity. Carmen, on the other hand, is completely out of control, sleeping with every man in sight, posing for pornographic pictures, doing hard drugs, and even killing a man. Thus, the degree to which the two sisters have vices are quite contrasting. Vivian is fundamentally ethical, even if she likes to explore the darker shadows of society. Carmen is pathologically sinful, and at the end, must be sent to a psychiatric institution.
Is Marlowe an ethical man?
Fundamentally, Marlowe has a strong ethical sense, and desires to do the right thing. Even though he often gets himself into trouble, must resort to killing Canino, and lies throughout to get the answers he needs, it is always in the service of the truth and in restoring justice. His hard drinking, heavy smoking, and flirtatious ways are all part of the contradictions of the noir hero. A lone wolf, the protagonist of a noir always seems more shadowy and sinful than he is. The hero of noir always knows that in order to get results and clean up the streets, one has to put up with and even participate in some of the world's ugliness. That is just part of the job. Marlowe typifies this cynical, world-weary, but ultimately ethical understanding of "how the world works."