Can a spine be sexy?

Is there an unwritten rule in book making that the cover is always the most challenging? Inarguably and unapologetically it is the cover that either wins or loses an audiences attention. The cover is the first thing that one sees when perusing a bookstore and perhaps, if you’re lucky like some, your books cover will be facing forward and flaunting itself for all the world to see. But if you’re unlucky, not meeting your monthly sales quota and your books are fruitlessly collecting dust on the top or bottom shelf, around the corner or off to one side, then all there is left to separate your book from others is the spine. So my question is, can a spine be sexy? Can it appeal to a larger audience, suggesting a longing to be held, or gently caressed?

So given the inevitable possibility that, in the end, all you have to work with is the spine, how do you handle the added pressure? And more importantly, what makes a spine sexy?