The script of "Back to the Future" was one of the most refused of Hollywood: more than forty times. No producer believed in this project of Robert Zemeckis and Bob Gale. Steven Spielberg imposed the film on Universal Studios, with Gale signing the script and Zemeckis directing. The director of "Jaws" will not regret it. In 1985, "Back to the Future" pulverized the box office and became a worldwide success, reinforced by two sequels in 1989 and 1990. Decade after decade, the popularity of this trilogy does not falter. Why this longevity while so many blockbusters sink into oblivion?