It's a post-apocalyptic world, but the apocalypse isn't due to zombies for a change. In fact, there's no explanation given for humanity's downfall in Cormac McCarthy's Pulitzer Prize winner The Road.
It doesn't really matter. You can insert your own reason: divine wrath, supervolcanoes, total war, environmental devastation, etc. The important thing is that it has happened, and the sad remnants of the human race are engaged in a nasty, seemingly futile struggle for survival in a dead world. The tale of a father and son journeying in desperation through the cold and the ash is the most gripping novel I've read in a long time, full of incredible sadness, beauty, and horror. Reading it is a little like being punched repeatedly in the stomach. Nevertheless, it remains quiet and understated, which contributes to the sense of reality - McCarthy leaves you feeling that this is exactly how a post-apocalyptic world would be.
