Okay, I've done 2600 words. A quick spin around campus revealed a stack of books, I think sent to me by Cambridge UP in payment for a book report. I put the books in a borrowed plastic bag and then I realized I didn't have wheels—the Prius is at the mender's. So I turned my exit into a brief constitutional. Now I'm back at the lab, as it were, in the humming center of the student union here, which is one of the places where I do quite a lot of writing.
Writing the whole book at once, as it were rhizomically, beginning from a number of starting points and seeing where things grow, is proving very conducive to getting this done.