Just so you know: after weeks and months of angsting about not knowing what my current book project (still in search of a pseudonym; maybe "The Tuna-Herder's Lament"?) was about, I did something that I've been doing more and more often: I just sat down and wrote. Shitty First Draft-level writing, for sure, full of square bracketed notes-to-self ["get some information on tuna-herding before the c13 tuna mortality..."], sentences that go on and on, and questions and avenues for exploration.
Let me tell you, it works. I still don't have any central question, but I have forward momentum. I have faith that I can do this.
Best yet: I have over 5,000 words.