This book was just not one I loved, though.
First of all, the first two thirds of the book is pretty depressing. The entire population of the earth, outside of a few survivors in space, is wiped out in a massive fiery apocalypse when innumerable pieces of the moon come crashing down. There is some interesting, and fairly detailed and realistic space science fiction regarding the survivors and how they cling to life in space , but the overall gloominess is aptly described by Cory Doctorow:
Stephenson builds up a sense of brutal inevitability, of humanity's insignificance in the cosmos that had me putting the book down for hours at a time, unable to read on (but my curiosity always overcame my sorrow). From: http://boingboing.net/2015/06/03/neal-stephensons-seveneves.htmlThe final portion of the book, when humanity is rebuilding, is more positive in its outlook, and much more speculative science fiction. It seemed too brief though, and leaves a lot of threads hanging. Perhaps because the first part of the book didn't put me in a particularly positive frame of mind, I found myself more skeptical of some elements of the world Stephenson creates, and the events that lead to it and within it.
If you're already a Stephenson fan: you'll probably want to read it.
If not: read one of his other books like Cryptonimicon.