Noir's most argued-over character is the femme fatale — a woman who uses wit and charm to bend men to her plans. She plays two roles at once. She feeds an old fear of powerful women. Yet she is often the sharpest mind in the film, leaving the male hero a step behind.

In Double Indemnity and The Postman Always Rings Twice, women gain power only by breaking the law, because 1940s screens offered them almost no other route to it. That tells you less about women than about the era that could only picture strong women as dangerous women.