As life's weirdness outpaced my ability to make up lies about it, I had to find a new place to write from. The second book became more personal. I was writing about fame. I still had plenty of jokes about Mole Men and hermit races and ridding your house of ex-models, but I also was writing in the only way I knew how some of the most personal material I knew I would write.
By the time I was writing the second one, I knew I would write a third, and I knew because I had contracted to write two more. I proposed it as a trilogy because all the best books are trilogies—at least The Lord of the Rings is.
It feels like a natural ending. I knew that the third book would be called That Is All because that is an email sign off I've been using since my literary agency days as a Radar O'Reilly-style joke from M*A*S*H. I didn't know much else other than it would have to come to an end. I didn't feel that the people in the world would have an appetite for an endless array of the same kind of goofball fake-history jokes. Eventually I was going to tell all of the ones that I knew how to tell and I was going to tell all the ones that people would accept from me.
Moreover, I also knew that these books were places where I was exploring not only humor but other things that I had to say. They had become meaningful in some way. To really finish properly, I would have to figure out what the whole project meant on some level and where I was going to end up and how I could possibly end a series of books that purported to contain complete world knowledge. The only option, ultimately, was the end of the world.
To go on and on and churn the stuff out would have been a possibility, but it just would have been a collection of gags. I realized that I wanted to create something — not necessarily something huge or serious or important — but something that was whole and would ultimately have a beginning, middle, and end. That takes a little bit more work—to finish something, than to keep it going forever.
There are lots of examples in history of things overstaying their welcome. The Thin Man movies, for instance. In terms of books, some of the later Encyclopedia Browns get a bit tedious.
Finishing a story is the second-hardest part after starting a story. You talk to someone like George R. R. Martin — that guy's got real problems. He's wrestling with the complexities of what happens when you build a world, how long do you stay in it, how faithful are you to it, and when do you decide enough is enough.
I don't want to flatter myself and say that I've built a world, but there's a certain consistency to the deranged alternate history that exists in these books. At some point, that world has to end. So why not have it split apart as the Century Toad breaks the world in half to go out into space after swallowing all the Mole Men? That just seems natural.