A review of The Road by McCarthy, from the New York Review of Books:
Charlton Heston and a savagely coiffed vixen, wrapped in animal skins, riding horseback along a desolate seashore, confronted by the spike-crowned ruin of the Statue of Liberty half buried in the sand: everyone knows how the world ends. First radiation, plague, an asteroid, or some other cataclysm kills most of humankind. The remnants mutate, lapse into feudalism, or revert to prehistoric brutality. Old cults are revived with their knives and brutal gods, while tiny noble bands cling to the tatters of the lost civilization, preserving knowledge of machinery, agriculture, and the missionary position against some future renascence, and confronting their ancestors’ legacy of greatness and destruction.
Ambivalence toward technology is the underlying theme, and thus we are accustomed to thinking of stories that depict the end of the world and its aftermath as essentially science fiction. These stories feel like science fiction, too, because typically they deal with the changed nature of society in the wake of cataclysm, the strange new priesthoods, the caste systems of the genetically stable, the worshipers of techno-death, the rigid pastoral theocracies in which mutants and machinery are taboo, etc.; for inevitably these new societies mirror and comment upon our own. Science fiction has always been a powerful instrument of satire, and thus it is often the satirist’s finger that pushes the button, or releases the killer bug.
This may help to explain why the post-apocalyptic mode has long attracted writers not generally considered part of the science fiction tradition. It’s one of the few subgenres of science fiction, along with stories of the near future (also friendly to satirists), that may be safely attempted by a mainstream writer without incurring too much damage to his or her credentials for seriousness.
More here.