I don't have the time to gamble on writing a book on spec right now, so I decided to put together a book proposal instead. In fact, that's how I sold MY GUN HAS BULLETS back in the early 90s to St. Martin's Press.
I've just finished writing the sample chapters. It's about 35,000 words and, dramatically speaking, the narrative equivalent of the first act of a three-act movie. It sets up the characters, the stakes and the obstacles ahead. In other words, everything is set in motion.
Over the next day or so I'll write up a punchy, broad-strokes outline of the rest of the novel. I don't know if the sample chapters are any good, or if my agent will think that the idea is marketable, or if any publisher in this economy will buy the book, but I am as satisified with it and pleased with myself for meeting my personal deadline of Dec. 1 to get the package done.
Now I'll set those characters aside (if I can) and concentrate on writing my next MONK book.