Do You Judge a Book by its Cover? Should You?

Recently I came across two really attractive book covers.  Of course perceived attractiveness is purely subjective, but I think most folks will find images on these covers attractive.

Of course we can argue about the relative merits of each cover regarding how well they relate to, or convey, the book's contents.  In an online world we could also have to consider how well each cover looks when it is scaled down to thumbnail size.

But right now I'm just talking about the visual appeal of the books in isolation, independent of the book's contents.  Do they pique your interest? Do you want to know what each book is about?

The book on the left is collection of poetry by Laini Mataka, who I recently called a powerful poet. The book in the middle is a historical romance novel by Cerece Rennie Murphy who I just praised for being supportive of AALBC.com.  The book on the right by Terrance Coffey is an award winning novel by a new participant on these forums.

Does knowing what each of these books are about make a difference?  Are they more or less appealing?

Do book covers matter?