Quote:Aliens have visited the Earth, and departed, leaving behind a number of artifacts of their incomprehensibly advanced technology. The places where such artifacts were left are areas of great danger, studded with space-time anomalies, known as Visitation Zones. A frontier culture arises along the margins of these Zones, peopled by "stalkers" who risk their lives in illegal expeditions to recover the artifacts, which do not obey known physical laws. The one most sought after, the "golden ball", is rumored to have the power to fulfill the deepest human wishes.

The novel's main protagonist is stalker Redrick "Red" Schuhart, initially employed as a lab assistant at the Harmont branch of the International Institute for Extraterrestrial Cultures, near the edge of Canada's Zone. He leads an expedition in search of a valuable artifact, as a result of which one of his colleagues is indirectly killed by an anomaly. Red later discovers that his girlfriend Guta is pregnant and wants to keep the child, despite rumours of monstrous births as a result of stalkers' exposure to the Zone's mutagen effect. They marry, against the wishes of Guta's family, and she gives birth to a mutant daughter, driving Red into the Zone one last time in order to find the golden sphere.

The name of the novel derives from a metaphor proposed by the character Dr. Valentine Pilman, who believes that the Zones and artifacts can be thought of as evidence of an extraterrestrial "roadside picnic". After the picnickers depart, nervous animals (i.e. humans) venture forth from the forest and discover the spilled motor oil, balloons, candy wrappers, and other detritus of the visit- which is commonplace to those who left it, but incomprehensible to those who find it.

Quote:# Andrei Tarkovsky's film Stalker is loosely adapted from the book, although with the Strugatsky brothers contributing to the script.
# In 2003, the Finnish theater company Circus Maximus produced a stage version of Roadside Picnic, called Stalker. Authorship of the play was credited to the Strugatskys and to M. Viljanen and M. Kanninen.
# While not direct adaptations, the video games S.T.A.L.K.E.R.: Shadow of Chernobyl, its prequel S.T.A.L.K.E.R.: Clear Sky and sequel S.T.A.L.K.E.R.: Call of Pripyat borrow from the original novel and from the film. The series has a wish-granting monolith similar to the Golden Sphere of the novel, or the Room of the Tarkovsky film. The series takes place in a fictionalized version of the Chernobyl Zone of Alienation and contains various physics-defying anomalies and strange "artifacts" that form within them.