Roger Ebert's Great Movies article on Out of the Past, in which he declares it one of the greatest of all films noirs, notes with relish the film's brilliant dialogue, coiling plotline and Mitchum's magnificent indifference to the world around him, exemplified by this later exchange when Ebert interviewed him and asked him about a particular line in the film:
""I don't, honest to God, know that I've ever actually seen the film."
"You've never seen it?"
"I'm sure I have, but it's been so long that I don't know.""
Back before anyone knew what a film noir was (not that anyone has a firm grasp on the concept now), Bosley Crowther in the New York Times was thoroughly confused by the film's complex plot, but enjoyed himself nonetheless (and understood more of why the film is great than he thought):
"But after this private detective has re-encountered an old girl friend (who originally double-crossed him after luring him to double-cross his boss, whom she had shot) and the two get elaborately criss-crossed in a plot to triple-cross our boy again, the involutions of the story become much too complex for us. The style is still sharp and realistic, the dialogue still crackles with verbal sparks and the action is still crisp and muscular, not to mention slightly wanton in spots. But the pattern and purpose of it is beyond our pedestrian ken. People get killed, the tough guys browbeat, the hero hurries—but we can't tell you why."
Finally, Out of the Past is such an exemplary film noir, that the best podcast on the subject takes its name from the film. Professors Shannon Clute and Richard Edwards, through 50 episodes beginning in July 2005, examined dozens of films noirs, both classic (The Maltese Falcon, The Big Sleep) and neo- (The Big Lebowski, Blade Runner). The episodes are a bit dry and academic (they sometimes seem like they're reading essays as opposed to having a discussion), but if, like me, you find that charming, then this show is essential. Their full archive is available, and while they've been off the air for the last year (writing a book about noir), there will apparently be new episodes again in 2011.