Back to the Future, the iconic 1985 American science fiction film directed by Robert Zemeckis and written by Zemeckis and Bob Gale, stars Michael J. Fox as teenager Marty McFly, who is accidentally sent from 1985 back to 1955 in a time-traveling DeLorean built by his eccentric friend Emmett "Doc" Brown (Christopher Lloyd). Upon arrival, Marty inadvertently prevents his future parents from falling in love, threatening his own existence, and must reconcile them before finding a way back to the future. A notable production detail involved Michael J. Fox replacing Eric Stoltz as Marty McFly shortly after filming began in November 1984, leading to significant re-shoots and an increased budget.

Despite these challenges and a rushed post-production, the film was a massive critical and commercial success, earning $381.1 million worldwide to become the highest-grossing film of 1985 and winning an Academy Award. Praised for its engaging story, humor, and performances, particularly by Fox and Lloyd, its theme song "The Power of Love" was also a hit. "Back to the Future" has since grown in esteem, recognized as one of the greatest science fiction films and selected for preservation in the National Film Registry in 2007, spawning two sequels and a beloved multimedia franchise that continues its enduring cultural impact.