A reserved and world-weary anti-hero, with some secrets behind his back? Check.
Gorgeous women as lethal as their incredible beauty? Check.
A shady villain mixed into some shady business? Check.
One treachery after another, until you don't know who's deceiving who? Check.
"Out of the Past" must be the title that immediately appears in movie filmmaking books about film noir and one can easily understand why. Jacques Torneur's expert direction of light and shadows perfectly captures the mood of this film genre; and the doomed characters can almost be considered as the ideal stereotypes of any film noir.
But most important of all, "Out of the Past" is an excellent picture, dark, complex, a classic on its own right, nevermind to which film genre it belongs to.