The View From Here magazine features an article on "The Integrity of Book Jackets." Here's an excerpt:
The book jacket has morphed into something that conforms to perceived stereotypes – blokes read books about war and action heroes and women about love and sex. Ultimately there is nothing wrong with jackets being genre specific – one only has to look at the original Penguins which were differentiated by colour and are now considered to be classics of their kind. Though it does seem silly to pigeon hole authors by cover image alone.
Read the rest, and see sample covers, here.