There has been much debate over the "Harry Potter" book covers for grownups. Personally, I'm not a fan of the idea in general, since I feel that reading the "Harry Potter" series is nothing to be ashamed of.
However, these new covers by M.S. Corley totally take it up one large retro notch and I love them. They are based on the designs of original Penguin covers and just look fantastic.
Implications - There was a time in my life when I didn't pay attention to book covers (maybe it had something to do with that old adage), but a friend of mine once said "Choose a book cover that you really like, because you will have to look at it for the rest of your life when you see that book."
Good advice. Enjoy these retro-styled great covers.