If you've seen this masterly thriller, directed by Carol Reed and written by Graham Greene, just a mention can bring it all back: the coiling plot about the black market in divided postwar Vienna; Orson Welles' (pictured) dash as that irresistible villain Harry Lime; and the plunk and tingle of Anton Karas' zither music. The filmmakers pit Yankee obviousness against European sophistication. All-American simplicity doesn't belong merely to the male lead, Holly Martins ( Joseph Cotten, at the peak of his form), who resembles the blundering Americans in Greene's other works about political hot spots. It also belongs in an amoral way to Martins' old friend Lime, a bouncing American boy who sees the world as a source of plunder. Martins, who pens pulp Westerns, sets out to disprove the charges against Lime set forth by the British Major Calloway (Trevor Howard, all eloquent gravity). Martins thinks he's writing a Western in real life, complete with cliffhanger chapter endings. But director Reed builds suspense without galloping action; his cliffhanger moments lead to ironic reversals or outright gags. Reed jacks up the tension through a series of oblique touches, most of which isolate Martins as a risky anomaly in a world where everything is for sale and the price is exacted in blood and hellfire. Much of the allure of "The Third Man," though, comes from its one lead woman: Alida Valli, who is ravishing and ravaged as Lime's lover and Martins' love object.