Chip Kidd, the guy who designed the cover of Murakami's latest, After Dark, talks about book covers in The Age.
He says he doesn't think the cover has much to do with selling books. More potent, he avers, are TV book shows. But "he strongly believes that a jacket can subtly interface with the text for an observant reader". I'm not sure what that means.
I guess when you've got your own Wikipedia page and a branded Web site (Good is Dead. The Work of Chip Kidd.), then you can virtually say what you like and everyone will think it's profound.
Possibly like Neville Brody, one of the greats of graphic design, he can get away with this sort of statement with impunity. After all, who's going to argue with you when you land commissions for the best books?
As "associate art director" at Alfred A. Knopf, Kidd must seem like royalty for students of the discipline. He "is universally recognized as an American master of contemporary book design" apparently. The 'associate' bit probably means that he doesn't have to work full-time to earn a living.