The classic noir film, and Bogart in his signature role as the hard-boiled detective Sam Spade. A tale of theft, murder, intrigue and the legendary Black Bird.
The awesome Peter Lorre plays Joel Cairo, an inept front-man for Sydney Greenstreet's BigBad. Once again Lorre is both bad and somehow innocent. It's a defining feature of his, and shows up again and again in his films, like M and Casablanca, where he also played opposite Bogie.
Mary Astor's femme fatale was so one-note that once she'd been caught in a lie once, it was impossible to believe anything she did again. The twists and turns that centered around her deceits were the centerpoint of the film. Greenstreet is excellent as the jovial mastermind.
But it's Bogart as the cynical Spade that makes this movie. A tough guy who uses everyone and plays each neatly against the other, Spade sleuths, deduces and manipulates his way through everything, including his perhaps-love affair with Astor. "Maybe I love you." He'll still sell her up the river, baby.