Tell All Books

Here's the gist of it: JFK, Jr. and his wife die in a flying accident. Time passes. Some guy writes a tell-all book detailing his affair with the Mrs. Kennedy...and private conversations between the two and all that. Granted, I haven't read it...and can assure you I won't. I still think I'm on safe ground commenting on this one, though.

I don't understand what the allure is about regarding:

a) anything Kennedy-related that isn't political in nature (Chappaquidick--sp?--being a notable exception, although I would argue that is somewhat political in nature)
b) why anyone would betray someone they cared about and proudly take cash for doing so (especially after they're dead and can't respond)
c) why anyone would care enough to pay 20-some-odd bucks for a tell-all book about these particular people

If anyone could enlighten me, please do so.