For your future entertainment:
Yes, the cover art features an hourglass full of skulls:
Did you notice my nosy kitty on the left?? Man, I can't wait to read this one.
And my thanks go out to everyone who has commented to help me find the few titles I'm missing. Especially Kat: the Bookmooch hint was awesome. I'm just figuring out what I own that I can part with, and then Hollow Skull will be mine. MINE!!! Miiiiiine!! (unless someone else gets it first.)