Took me a long time to finish this book both because it is really super long (it’s like three or four different narrative arcs in one which is NOT BAD) but also because I liked it and didn’t want it to end. It’s a complicated story of something bad happening (moon explodes, who knows why) and then humans have to get off of earth in a hurry (two years) and how that all works. Cut ahead 5000 years and we look at how things turned out. Both parts of the book are interesting, the space stuff which is meticulously explained (which sort of explains why the book is so long) is a little more credible-feeling than some of the race theory stuff later on in the book and “just so” explanations for why the new society does and doesn’t have certain kinds of technology. A great and well-recommended read.