It's probably because
(a)
sundancekat killed me with her brain powers from afar, because 2 days before the publications go to press I sent her 8 or 9 guest bios...
(b) I tripped over one of my cuddly, but brainless, cats
(c) I sneezed hard enough to stop my heart
(d) Some last-minute guest craziness ensued, like requesting changes to stuff that was agreed months ago
(e) My brain got too full and gave me an aneurysm
Doubtless, knowing my friends, I'd be shambling about anyway, having been either animated (ironic) or otherwise restored to zombielike mobility...