AS THE 20TH CENTURY recedes, film noir seems more an attitude than an actual genre. The phrase itself—which wasn't coined until after the fact, by French critics—refers to gritty, bleak American thrillers from the '40s and '50s, almost always shot in black and white. There's usually a murder and a femme fatale to accompany it; trench coats, fedoras, and plumes of cigarette smoke are de rigueur. But watching the 11 selections in this year's edition of Cinema 21's noir series, the commonality doesn't have so much to do with murders, or dames, or nicotine. These films are all about love—more specifically, about passion and obsession, about some poor johnny getting dizzy over a skirt.

That's the case with 1944's Laura, in which Dana Andrews' detective falls head over heels for a picture of murder victim Gene Tierney (who can blame him?). In 1946's The Postman Always Rings Twice, John Garfield attempts to off Lana Turner's older husband. Love, similarly, runs through Nicholas Ray's masterful In a Lonely Place (1950), in which Bogart's not-so-nice guy is accused of murder—but the film is more interested in his troubled, wild relationship with Gloria Grahame. It's a stunning movie, crazily romantic and monumentally fucked up, just like most love affairs.

1950's terrific Gun Crazy dwells in the inherent romanticism of lovers on the run (a theme revisited years later in Bonnie and Clyde and Badlands); here, circus sharpshooters John Dall and Peggy Cummins become bank robbers and quickly run out of road and rope. The family drama of 1945's Mildred Pierce is bookended by an excellent noir framework, and Fritz Lang's The Big Heat (1953) follows an honest detective taking down his entire, corrupt police bureau. Jules Dassin's Night and the City (1950) transplants noir conventions to London, where American hustler Richard Widmark tries to take over the city's wrestling racket; it includes some great-looking chases and the classic wrestling match between Stanislaus Zbyszko and Mike Mazurki.

Speaking of fight scenes, there's an incredible one in a tiny train compartment in 1952's The Narrow Margin (it was later borrowed wholesale for From Russia with Love). Shot almost entirely aboard that claustrophobic train, Margin is one of the true gems in the series, a lean, razor-sharp thriller about a cop escorting a witness from Chicago to LA with baddies in pursuit.

The series includes three neo-noirs from later decades, too, which update noir conventions with a few twists—like color. 1981's outstanding Body Heat is Lawrence Kasdan's first and best film, asking: What happens when you add graphic sex to a film noir? (Answer: lurid awesomeness.) Robert Altman's The Long Goodbye is a riff on Rip Van Winkle, with Philip Marlowe (Elliott Gould) about 20 years out of step with 1973 Los Angeles. It removes all the passion from classic noir tropes in favor of pot-haze detachment and washed-out pastels, and the result, surprisingly, feels far more dated than noirs from the '40s and '50s. Meanwhile, the Coen brothers' 1985 debut Blood Simple is a breezy, bloody, wickedly funny Texas thriller that does noir conventions a solid.

A 13-day festival pass is only $40, and individual shows are $6. You can't go wrong with any of the selections, but if time or dollars are tight, let me steer you toward The Narrow Margin, In a Lonely Place, and Body Heat.