With the past two months, I have read — for various reasons — four different novels laying out apocalyptic events within the United States. Here are the novels, in the order I read (or re-read) them, and with the reasons why I read them: — Lucifer’s Hammer by Larry Niven and Jerry Pournelle (1977): a comet fragments and strikes the Earth in numerous places, collapsing much of world civilization, including the United States. I’ve read this several times before; I saw it cited on a blog (Samizdata) in a discussion on “the best end-of-the-world novels” and decided to dig it out and read it again.