Richard Mason brought up an excellent point. Forget fonts and cover illustrations; sometimes the publisher tries to trick the reader about who wrote the book.
There are a couple of variants on this:
1) Famous Author Presents. Publisher pays Famous Author beaucoup bucks to use his name on cover of book written by Up-and-coming Author. FA gets $$$, UA gets published, publisher makes more sales, everyone's happy except the reader who buys this book thinking it was written by FA.
Great big 'Isaac Asimov'. Little teeny John Barnes.
2) 'Collaborations'. Often books in a series, sometimes not, these are books co-written by one FA and one UA. Sometimes they are good, sometimes they are bad, sometimes they are awful. Who knows how much time the FA actually put into writing? Judging from some of the results, sometimes it's not very much time. It's hard to tell. While it does get the UA's name out there in front of fans, if it's a bad book, is that really good for their career?
For example, I loved the Carolus Rex books by Andre North and Rosemary Edghill (also known as Eluki Bes Shahar). I hated the Bedlam books by Edghill and Mercedes Lackey.
I love the way Edghill's name is hidden in the light-colored area on the Lackey cover.
I can't deny it's been very beneficial for some authors; for example, I remember seeing Elizabeth Moon's collaborations with Anne McCaffrey soon before Moon graduated to wide success in her independent work.
Here's another great collaboration cover. McCaffrey's name on top: Jody Lynn Nye's name on the bottom.
3) Ghostwriters. Did anyone really believe for a minute that William Shatner wrote the Tekwar series? Yet, there his name is. This was probably a 'work-for-hire' written by some UA who doesn't get either his name on it OR royalties. Not a good deal for him.
Worse, in terms of 'defrauding' the reader, are works 'by' a FA who has farms out his work to other people. The reader is expecting one level of quality and sometimes a very different level is delivered. There are persistent rumours about certain very high-volume authors who shall remain nameless.
Have you been burned by any particularly deceptive book covers, or particularly egregious 'collaborations'? Please share - I'll go browsing for some more covers today.
UPDATE: Here's a great one.
WHO wrote that?