This is a good collaboration between two great SF authors. It tells the story of an apocalyptic event, namely a big comet hitting the earth, quite realistically. The authors mention that their book was referenced several years after it was published when a comet (Shoemaker-Levy) hit Jupiter and the impact was quite similar to the way the authors described it.

Of course as many good SF authors they are more interested in the aftermath of such a disaster, in the way it affects the lives of the survivors and the way it changes society.

I found the book a bit long-winded in some sections but thoroughly enjoyed its depiction of the event and the small, fragile societies that the survivors tried to build after the event.

Heartily recommended.