Seth Godin (internet marketing guru and all around interesting guy) weighs in on book covers in a recent blog post.
Tactically, the cover sells the back cover, the back cover sells the flap and by then you’ve sold the book.
This is a new thought for me, and an interesting one. I’ve found that one of the easiest ways to tell a good designer from a great designer is by the quality of their back covers. Mine are fairly horrible. Something to work on.
Also note that this isn’t the first time Godin has mentioned book covers:
• Do you judge a book by its cover
• Judging a book by its cover (Wherein he calls a Chip Kidd cover “lousy”)