Science fiction has long been considered by some experts to be a lesser genre than traditional dramas and character studies. Because it lends itself so easily to exploitation, science fiction isn’t always given the respect it deserves. Sure, it tends to be a box office winner, as evidenced by the fact that more than half of the all-time domestic grossing films fit easily in that genre (with at least two more – Pirates of the Caribbean: Dead Man’s Chest and Shrek 2 – marginally related as genre films). Still, some still consider science fiction something not to be taken seriously. It is for this reason that “legitimate” film directors might shy away from science fiction in lieu of more important or significant projects. However, many directors got their start or their earliest fame from working in science fiction and other allegedly exploitative and pulp genres. This week’s release of Prometheus reminds us that even though Ridley Scott has directed historical epics (Gladiator and Kingdom of Heaven), military action films (Black Hawk Down), crime thrillers (American Gangster) and straight dramas (Thelma & Louise), he got his start in science fiction with Alien and Blade Runner. Scott isn’t the only director to begin a successful career in science fiction. Here are seven other directors who started out or received some of their earliest success in this genre.