Paul Schrader was in meltdown in 1972. Drinking heavily, living in his car, he was hospitalised with a gastric ulcer. There he read about Arthur Bremer's attempt to assassinate Alabama Governor George Wallace: the story was the germ of his screenplay for Taxi Driver (1976). Executives at Columbia hated the script, but when Martin Scorsese and Robert De Niro, who were flying high after the triumphs of Mean Streets (1973) and The Godfather Part II (1974), signed up, Taxi Driver became too good a package to refuse.Scorsese transformed the script into what is now considered one of the two or three definitive films of the 1970s. De Niro is mesmerising as Travis Bickle - pent-up, bigoted, steadily slipping into psychosis, the personification of American masculinity post-Vietnam. Cybill Shepherd and Jodie Foster give fine support and Scorsese brought in Bernard Herrmann, the greatest of film composers, to write what turned out to be his last score. Crucially, Scorsese rooted Taxi Driver in its New York locations, tuning the film's violence into the hard reality of the city. Technically thrilling though it is, Taxi Driver is profoundly disturbing - finding, as Amy Taubin shows, racism, misogyny and gun fetishism at the heart of American culture.In her foreword to this special edition, published to celebrate the 20th anniversary of the BFI Film Classics series, Amy Taubin considers Taxi Driver anew in the context of contemporary politics of race and masculinity in the US, and draws on an exclusive interview with Robert De Niro about his memories of making the film.