No American detective novel written in the thirties would be complete without the figure of the "femme fatale," a French term meaning deadly woman. A femme fatale is an irresistibly beautiful woman who uses her sexuality to seduce men and lure them into dangerous situations to serve her own selfish interests. There are a fair few of these in The Big Sleep, but none of them is quite the dynamo that Vivian turns out to be.
Vivian is the wife of Rusty Regan and the older sister of Carmen. She's just as much of a knockout as her kid sister, but in place of Carmen's blonde hair and slate-gray eyes, Vivian has dark, wiry hair and coal black eyes. Whereas Carmen comes off as the delicate, innocent type, Vivian looks strong and in control—like the classic femme fatales we've come to know and love:
She was worth a stare. She was trouble. She was stretched out on a modernistic chaise-lounge with her slippers off, so I stared at her legs in the sheerest silk stockings. They seemed to be arranged to stare at. They were visible to the knee and one of them well beyond. The knees were dimpled, not bony and sharp. The calves were beautiful, the ankles long and slim […] She was tall and rangy and strong-looking. […] She had a good mouth and a good chin. There was a sulky droop to her lips and the lower lip was full. (3.2)
Okay, let's go down the Femme Fatale Checklist. Irresistibly beautiful? Check. Seductive? Check. Trouble? Double check. Like her sister, Vivian knows how attractive she is to men and she isn't afraid to use her beauty to get what she wants. Halfway through the novel, Vivian even tries to seduce Marlowe by kissing him in the car after they leave Eddie Mars' club. All classic attributes of a femme fatale.
But as we mention in the Tough-O-Meter section, Chandler didn't want his novel to be just like any other cliché, predictable detective story. He wanted his characters to have psychological depth and complexity. So he wasn't about to make his female characters fit nice and neat into the standard convention of the femme fatale. So what does he do? He gives Vivian some recognizable features of the femme fatale (beauty, charm, seductiveness), but then he also makes her the protective sister and daughter, who's just trying to keep the family name clean.
The interactions between Marlowe and Vivian vary from petty fights to name-calling to potential romance. Marlowe doesn't seem to think very highly of Vivian, and does his best to resist her advances because he doesn't trust her. When they share a kiss, Marlowe admits his attraction to her, but due to his personal code of chivalry, he won't pursue a romance with Vivian since he's working on a case for her father.
On Vivian's end, it's more difficult to figure out her real feelings toward Marlowe. She's someone who is used to getting her own way, so she is both annoyed and impressed by Marlowe's ability to resist her wiles. She also seems to be hiding something, so we can't help but think that all the charm she showers on Marlow is really just her attempt to distract him from the case.
In the final pages of the novel, Marlowe discovers that Vivian had known all along that Carmen iced her husband. But instead of going to the authorities, Vivian paid off Eddie Mars to get rid of the body both to protect Carmen and to keep her father from finding out about Rusty's death. Why? Why defend her sister for murdering her husband? Is that sisterly love, or something more sinister?
According to the lady herself, "If dad knew, he would call them [the police] instantly and tell them the whole story. And sometime in that night he would die. It's not his dying—it's what he would be thinking just before he died. Rusty wasn't a bad fellow. […] He just didn't mean anything to me, one way or another, alive or dead, compared with keeping it from dad" (196).
It definitely sounds like Vivian genuinely cares about her father. So was it immoral of Vivian to try to cover up the murder or was she trying to protect her family from harm? On the one hand, she does mislead Marlowe by hiding the truth from him. But on the other hand, Vivian's desire to keep the General from finding out that Carmen killed Rusty seems to indicate that Vivian wants to protect her father's feelings. By portraying Vivian as a psychologically complex character, with shadowy motives, Chandler makes it impossible for us to define her one way or another.