At first blush, apocalypse seems like an odd subject for sci-fi mega-author Neal Stephenson. His earlier novels, each the size of a small treasure chest, are stuffed to bursting with the nifty baubles of civilization. Whether writing of near-future nanotech or 17th-century financial innovations, he revels in society's scale and variety.

So why blow it all up?

Seveneves begins at an unspecified date in the near future. An unknown object, perhaps a small black hole, has collided with the moon, busting it into seven chunks. So far, things don't look too dire. Only a few people have been killed, and even the tides are still going in and out, since those seven fragments add up to the same cumulative mass.

But some brainy types soon realize the moon chunks will disintegrate into millions of smaller pebbles, causing the worst meteor shower the modern Earth has ever seen. The incoming rocks will superheat the atmosphere, and everything on the surface will be fried.

For an author like Nevil Shute or Cormac McCarthy, this kind of scenario occasions poignant meditations on the frailty of human affairs. Not so for Stephenson. Stephen King purged the Earth to set the stage for a Manichean epic; James Howard Kunstler wiped the planet's slate to construct a craftsman's paradise; Yahweh cleaned humanity's clock to, well, mostly just to show he could, and Stephenson's doomsday is likewise something of a convenient catastrophe.

In an earlier novel, Anathem, Stephenson took a long and often elegiac view of humankind's intellectual heritage. In Seveneves, he doesn't spend much time pondering what's been and gone, but instead uses his apocalypse to set up the stakes for a thrilling hi-tech game.

That game comes with a timer. Earth has two years until the moon goes ballistic. This gives humanity just enough time to cobble together a preserve for the planet's genetic heritage, a kind of orbital ark consisting of a swarm of tiny spaceships oriented around a souped-up version of the International Space Station.

This is probably an impossible task, but setting his story in the near future allows Stephenson to toss in a handful of power-ups. The ISS comes equipped with a captured asteroid, a sort of giant pet rock that serves variously as ballast, aegis, and resource. Earth's relict population can also make use of some clever cost-effective life-support systems, a passel of wonderfully versatile mining robots, and, later, thanks to the efforts of a maverick millionaire, a harvested comet shard.

And so it goes, for near a thousand pages. Stephenson never thinks small, and this is a bloated book about big ideas. Apocalyptic tales have an unpleasant way of evolving (or degenerating) into elitist parables, in which extreme pressures serve to separate the worthy from the worthless, the men from the boys…and, in a kind of atavistic sexism, the boys from the girls, as the collapse of enlightened society is frequently perceived as entailing a return to old-school gender roles.

All this is particularly true when the crisis is a Damoclesian one, hanging over the characters' heads and giving them time to plan their actions. Whom will they save? Whom will they leave behind? What moral sacrifices will they make to ensure their survival?

In choosing to effectively reboot the human race, Stephenson knows he has a hot potato in his hands. His solution is to split the skin, add some chives and bacon, and slather on the sour cream. Race, reproduction, class, eugenics, intelligence, digs at social media — it's all here, every hot-button topic you can imagine. That species of reader whose main ambition is to act as a kind of human Geiger counter, scanning cultural products for radioactive content, will find plenty to set his needles wagging.

Eventually, the entire population of the planet gets pounded, stabbed, burned, frozen, zapped, and suffocated down to eight survivors, seven of whom are fertile women — the seven Eves of the book’s title — responsible for gestating the future human race. The decisions they make are, to say the least, radical.

Longtime Stephenson readers will recognize the author's signature quirks: a hasty and cluttered denouement, a boyish delight in kooky contrivances, and a seemingly untamable addiction to talky exposition.

But why quibble? This is an amazing book in every sense of the word — crammed with thought experiments, wild prognostications, and brilliant set pieces. It's the sort of novel in which 5,000 years can go by between chapters; the sort of novel in which the characters themselves describe the story as "epic" without it sounding forced or presumptuous; the sort of novel that makes you remember just how cool it is to be an animal with an imagination.

Part space-survival story, part semi-mythic quest, Seveneves' greatest achievement, in a cultural moment choked with pessimism, is to turn the end of the world into an inspiring plot development. Sure, 3,000 years of history go up in smoke, but what a chance for humanity to strut its stuff. The inventiveness of the book itself is a warrant for its optimism. Go ahead. Bring on the apocalypse. Stephenson's intellect, at least, is irrepressible.

Nick Wolven's fiction has appeared in Asimov's Science Fiction and the New England Review, and many other publications, and is forthcoming in the Magazine of Fantasy & Science Fiction.