"I'm God's lonely man," says Travis Bickle, played by Robert De Niro in one of his finest and most memorable performances. Travis, the protagonist and focal point of Taxi Driver, is severely out of his element in New York City, though it's hard to imagine where else he would fit in; he goes through life as if the world speaks a dialect unknown to him. He seems incapable of relating to anyone beyond superficial pleasantries or casual violence, and when he does attempt to reach out to others -- to beautiful campaign manager Betsy (Cybil Shepherd), to philosophical cabbie Wizard (Peter Boyle), or to teenage runaway-turned-prostitute Iris (Jodie Foster) -- he runs into a brick wall despite his best intentions, as he can't fully comprehend others and they can't fathom him. Screenwriter Paul Schrader and director Martin Scorsese place this isolated, potentially volatile man in New York City, depicted as a grimly stylized hell on Earth, where noise, filth, directionless rage, and dirty sex (both morally and literally) surround him at all turns. When Travis attempts to transform himself into an avenging angel who will "wash some of the real scum off the street," his murder spree follows a terrible and inevitable logic: he is a bomb built to explode, like the proverbial gun which, when produced in the first act, must go off in the third. While De Niro's masterful performance brings Travis to vivid life, it's Scorsese's dynamic, idiosyncratic visual storytelling (given an invaluable assist by cinematographer Michael Chapman) that provides the perfect narrative context. Capturing New York's underbelly with a palate of reds and yellows that burn with an evil glow, Scorsese fills the story with tiny details and offhand moments that form the fully rounded reality of Travis' fallen world. If De Niro produced one of film's most troubling portraits of a lost soul, Scorsese created a painfully vivid purgatory for him to live in, and, alongside Raging Bull, Taxi Driver marks the finest work of this actor/director team.