I started writing the book without realizing I was writing a book. That sounds stupid, but it's true. I'd been trying and failing to make a different manuscript work, and I thought I was just taking a break by writing some short stories. I'm not a very good short story writer - the amazing compression that is required for short stories doesn't come easily to me. But anyway, I thought I'd try to write some short stories. And a structure took shape - I stumbled upon it.