Stalker (Russian: ) is a 1979 science fiction film directed by Andrei Tarkovsky, with a screenplay written by Boris and Arkady Strugatsky, loosely based on their novel Roadside Picnic. It depicts an expedition led by the Stalker (guide) to bring his two clients to a site known as "the Zone", which has the supposed potential to fulfill a person's innermost desires. The title of the film, which is the same in Russian and English, is derived from the English word to stalk in the traditional meaning of approaching furtively and not related to the contemporary meaning of harassing. In the film a stalker is a professional guide to the zone, someone who crosses the border into the forbidden zone with a specific goal. The sparseness of exposition leads to ambiguity as to the nature of The Zone. The film suggests that the Zone is the site of an alien spaceship landing or meteor strike, or perhaps is imaginary.