Stalker

Stalker has several different meanings:
A person who stalks
The name of a novel by Boris and Arkady Strugatsky. The novel was called Roadside Picnic and was written in 1972.
A short story based on the novel, called Stalker
A 1979 movie by Andrei Tarkovsky, called Stalker based on the novel Roadside Picnic
S.T.A.L.K.E.R.: Shadow of Chernobyl, a computer game