Neal Stephenson

Having lived in a monastery since childhood, away from the violent upheavals of the outside world, Raz becomes one of a group of formerly cloistered scholars who are appointed by a fear-driven higher power to avert an impending catastrophe.

Five thousand years later after a catastrophic event rendered the Earth a ticking time bomb, the progeny of a handful of outer space explorers--seven distinct races now three billion strong--embark on yet another audacious journey: to return to Earth.

"Boston, present day. A young man from a shadowy government agency shows up at an Ivy League university and offers an eminent professor a lot of money to study a trove of recently discovered old documents. The only condition: the professor must sign an NDA that would preclude him from publishing his findings, should they be significant. The professor refuses and tells the young man to get lost. On his way out, he bumps into a young woman--a low-on-the-totem-pole...