Those of us who have written books, have thought of writing books, or even just know people who have written books think with some regularity about book covers: the ones we admire, the ones we imagine someday having, and the ones that do no one no favors.
There's not a lot of money for cover art in academic book publishing--you're a total rockstar if your cover gets a four- rather than two-color palette--and the designs tend to range from the uninspired to the reasonably attractive. Still, if there's money for a cover image at all, it usually bears some relationship to the work between the boards.
But not always. My copy of Leviathan, for example, has a close-up of the prow of a massive, early 20th-century ocean liner. (Um, I get what you were going for, Mr. Design Dude? But I don't know why you were going for it.)
However, nothing--nothing!--holds a candle to the original cover art for Stanley Fish's Self-Consuming Artifacts: The Experience of Seventeenth-Century Literature (1972):
Just to be clear: this is a book with chapters on the works of Francis Bacon, John Milton, George Herbert, John Bunyan, Thomas Browne, and Robert Burton. It is not a book about. . . well, about whatever's going on in that cover image.
(Click on the image. You have to see it in its full, terrifying glory.)
Seriously, I don't even know what to do with that cover. It's hideous and compelling at the same time, and I'm sure the Fishman loved it. I bet he chose the image himself.*
Can anyone beat that cover for freakishness, bizarritude, or barely-minimal relevance to the book it contains?
*This, by contrast, is the depressing cover of the edition that's currently in print.