Roadside Picnic is a novel written in Soviet Russia, but set in the West. When I read it, I got the impression it was set in Britain, though I am not entirely sure. It's been turned into a movie by Tarkovsky (who also made Solaris), and it has inspired a series of videogames. As far as I know, both stray from the book.
First things first: do not read the introduction until after you've read the book. It assumes you're familiar with the text and analyses it, offering spoilers.
The novel takes place at three different times, each several years after the other. It's set in the aftermath of an alien visit, which has left large geographical areas uninhabitable, filled with uncanny, incomprehensible and deadly features. These areas are the Zones.
Humans have gotten over their terror about the alien visit, and are largely trying to ignore it. However, they are also intrigued and bothered by the alien artefacts and effects. Scientists try to understand and analyse. There's a black market. There are smugglers, despite the dangers both from the Zone and from the police forces and snipers.
Redrick Schuhart is one such explorer / smuggler. Their profession is known as Stalkers. He's slick, dishonest, tough and quite uncaring. He slugs a lot of Vodka and deals with a lot of shady characters. Each of the three episodes of the novel deals with a significant period in his life / major turning points in his career as a stalker, but, as he is a very Russian guy, his reaction to everything is understated and sardonic. He reminded me of Europe in Autumn's protagonist, Rudy: I imagine the two would get along and be, insofar as they are capable of it, close friends.
There aren't really any characters who are easy to empathise with. It's a novel about worn-out people muddling by in the shadows of an uncanny disaster they cannot comprehend, but which they seek to exploit, in a suitably half-hearted and downtrodden manner.
What makes the novel stand out are the ideas that the introduction gives away, the notions that give the book its title. About 2/3 of the way through, they are the subject of a scientist's drunken rant. It's a clever and rare perspective. I have no doubt that it was influential and original when it was written.
For today's readers, the lack of emotional investment in characters and the lack of discernible direction for much of the plot are likely to try the patience. I found the book quite readable, for a Russian one. Much more so than Solaris. Still, I wouldn't call it a page turner.