This is the first bok I've ever read by Neal Stephenson and I thoroughly enjoyed it. It is long, but I burned through it because I found the story fascinating.
True, it is really two books, some would say even three.
"Book 1" starts out as the story of the end of Earth, triggered by the misterous destruction of the moon. Humans desperately scramble to make a plan to survive the looming destruction.
"Book 2" is the chronicle of those who made it out of Earth. The last existing humans. It is the story of their struggle for survival.
"Book 3" is set 5000 years in the future, when humanity returns to Earth and tries to claim it back as home. But society is so different then.
What I loved about the book is how ambitious and grandiose it is. I loved the huge ideas it tackles, and the technical detail of all these imagined technologies. I loved it's descriptions of space and its understanding of orbital physics, to the point of actually teaching me concepts such as Nadir, Zenith, Apogee and Perigee. (Go Science!)
I don't give it 5/5 because I felt that while it excelled in the science and technical details, it lacked a bit in character development and depth. Characters are a bit uni-dimensional and predictable, although it does have a bunch of kick-ass female heroes. :)
I really hope Seveneves is just the beginning of a larger trilogy, as the universe it creates is so elaborate, meticulous and complex it really deserves further exploration.
Also because it ends on a real cliffhanger. But I won't spoil it!
If you like space set, high stakes, apocalyptic and imaginative stories... I would say this book is for you.