If you haven't written a book, or if you're one of the lucky writers who doesn't suffer the dread scourge of post-novel ennui (I understand there are a few), it's the state immortalized by Mr. Gorey in the immortal phrase quoted in this icon. (And if you are or want to be a writer, or you live with one, may I recommend Gorey's The Unstrung Harp as the ultimate guide to the care and feeding of same?) A state, more or less, of semi-complete mental and emotional exhaustion brought on by the rather profound cerebral exertion of finishing a book. (Which is not an easy thing to do. If you've ever had the experience of Finals Week, or writing a dissertation, finishing a novel is about the same thing. You wind up wandering around for about a week afterwards forgetting what you were saying in the middle of the sentence, sleeping too much, and putting the crackers away in the freezer.)
I am there now. It's a state comprised of a combination of restlessness, distractibility, and lethargy. And it can be shaken off or postponed, but the debt has to be paid. (Actually, I'm considering taking a crack at some more of that Dust proposal, because I know a bunch of it currently and if I get it done, that means I get to have an actual long-term collapse the sooner, rather than the measly week I have alloted myself now.
After that, my next deadline is April 1, a short novella for an SFBC anthology of space opera edited by Gardner Dozois, and then I have All the Windwracked Stars and Ink & Pen due in early November. I'm guessing the Dust deadline will be earlier than that--assuming Spectra buys it--because Undertow comes out in August and they seem to like to have the next book in hand when the previous one ships.
So, my tentative 2007 schedule, not counting short fiction publications:
Jan 15 - Deliver Dust proposal
April 1 - Deliver "Periastron."
May - New Amsterdam publication (I'm sure there will be galleys and things between now and then, of course)
July - Whiskey & Water publication
August - Undertow publication, deliver Dust
September - A Companion to Wolves publication
November 1 - Deliver Ink & Pen and All the Windwracked Stars
December 31 - I'd like to have "Bone & Jewel Creatures" done by then.