And the proofs are also in my hands, as you can see here:
So: This is the cover proof, which I have to approve for color and final text. Both at work and here, the cover proofs come with clear plastic overlays, one for each of the various kinds of cover effects. Here I'm just getting a gloss coating, so there's just one overlay; but if I were getting, say, matte lamination along with spot gloss (aka "spot UV"), then there would be two overlays, one showing the matte layer, one showing the gloss layer, each one positioned precisely to show what areas of the color proof that effect would cover.
And then there can also be overlays for embossing, debossing, foil color #1, foil color #2, printing on foil . . . all the myriad ways in which you can bling up a book, for better or worse. Each individual effect costs money -- an additional three to eighteen cents per effect, per book (costs quoted off the top of my head), depending on the effect and the amount it's used and the print run and so forth -- which goes directly to the unit cost of the book. So the more effects a book has, the higher the unit cost, and the more expensive the book itself might be as well; but that can also pay off, if the effects result in more attention from buyers or a more attractive package overall.
ETA, 2/17/11: The cover proof was fine, but I decided to make three corrections to the interior: one italicization that went wonky in the last round of proofing; one incorrect word I'd missed; and one fairly large typo I couldn't let stand. Cost of making these corrections: $52. Feeling like my book is that much more complete: Priceless.