William Gibson's 1984 Neuromancer is pretty dense. It begins right in the middle of things, and never explains the science fiction world's background. We the readers must piece it together on our own. Initially, main character Case seems like a sort of deadbeat alcoholic American living in future Japan. Well, we assume he's American. North America is referred to only as the Sprawl.
We figure out that some sort of apocalyptic event happened to North America (I specify "North America" instead of "United States" because Gibson is American-Canadian), and there's a wave of shady immigrants from this Sprawl now living in Japan. The story takes place in Chiba, a real-life suburb of Tokyo. This is important. I don't think the world of Neuromancer would seem as gritty or real if it took place on some distant planet; the fact that it's a place that exists in the real world, even if it's across the Pacific, makes it a bit more identifiable.
The iconic first line of the novel--"The sky above the port was the color of television, turned to a dead channel"--gives way to an opening scene in a bar, with a one-armed futuristic bartender. It's all very evocative, but incredibly foreign as well. We've seen plenty of stories about pubs with troubled inhabitants, but the bartender Ratz with his prosthetic limb makes the scene alien to us.
I've got a point of reference, though: Ridley Scott's Blade Runner, in theaters only two years prior to Neuromancer's release. Both works take place in a dystopian future where Americans bump elbows with the Japanese, and as a result, through my reading of the book I imagine Case as Harrison Ford.
But there's really no exposition. Gibson assumes the reader has a certain level of intelligence, and we have to put the puzzle together ourselves.