From Google video:
"Stalker (Сталкер)
2:34:55 - 2 years ago
Directed by: Andrei Tarkovsky;
Produced by: Aleksandra Demidova;
Written by: Arkadi Strugatsky, Boris Strugatsky;
Starring: Alexander Kaidanovsky, Anatoli Solonitsyn, Nikolai Grinko;
Music by: Eduard Artemyev;
Distributed by: Mosfilm;
Release date: August 1979 (Soviet Union);
Running time: 163 min;
Language: Russian;
Subtitle: English;

Description: Near a gray and unnamed city is the Zone, an alien place guarded by barbed wire and soldiers. Over his wife's numerous objections, a man rises in the dead of night: he's a stalker, one of a handful who have the mental gifts (and who risk imprisonment) to lead people into the Zone to the Room, a place where one's secret hopes come true. That night, he takes two people into the Zone: a popular writer who is burned out, cynical, and questioning his genius; and a quiet scientist more concerned about his knapsack than the journey. In the deserted Zone, the approach to the Room must be indirect. As they draw near, the rules seem to change and the stalker faces a crisis."

From gamepron (http://www.gamepron.com/news/2010/07/13/s-t-a-l-k-e-r-the-original-film-now-free-online/):
"While plenty of people have played S.T.A.L.K.E.R.: Shadow of Chernobyl, not many of them realise the game takes elements from both a book and a film. The book, Roadside Picnic by Arkady and Boris Strugatsky, has been freely available online for a while now, but it’s taken a little longer for Andrei Tarkovsky’s film adaptation – Stalker – to make it onto the net.
Now, thanks to Film Annex, gamers who also like a bit of cinema can sit down and enjoy the movie which inspired the series of open-world sandbox titles."