Let us suppose that you are an author with a consistently hard-cover original line of action/fantasy-horror novels, a nice long backlist, and you made two mistakes. The first mistake is that you decided to join a previous series with the current series (hah, new printings!) and as a result incorporated a definite timeline for the end of the world. The second mistake is that you already wrote the end-of-the-world book in the previous series...
Did I mention that the timeline of the new series is about to crash into the end-of-the-world from the first series?
The answer, then, is to write prequels, fill-ins, and rewrite the end-of-the-world book.
_The Dark at the End_, F. Paul Wilson.
Which is the last possible book to write before _Nightworld_, the end-of-the-world book.
Did I mention that the timeline of the new series is about to crash into the end-of-the-world from the first series?
The answer, then, is to write prequels, fill-ins, and rewrite the end-of-the-world book.
_The Dark at the End_, F. Paul Wilson.
Which is the last possible book to write before _Nightworld_, the end-of-the-world book.