A catastrophic event renders the earth a ticking time bomb. In a feverish race against the inevitable, nations around the globe band together to devise an ambitious plan to ensure the survival of humanity far beyond our atmosphere, in outer space.  Only a handful of survivors remain . . .Five thousand years later, their progeny—seven distinct races now three billion strong—embark on yet another audacious journey into the unknown . . .to an alien world utterly transformed by cataclysm and time: Earth. Neal Stephenson combines science, philosophy,  psychology, & literature in a magnificent work of speculative fiction that offers a portrait of a future that is both extraordinary & eerily recognizable.