I just heard from the copy editor--life is screwing with her, so she asked if it would be OK to push her deadline back to mid-April. I said sure. It should work: I should still be able to release the book in May if it comes back then.

And it means that instead of just having a one-week window to resume work on Trials, which hardly seemed worth doing, I now have a three-week window, which is a really significant chunk of time!