Secrets?

Many book titles, (and I'm not discrimating against any particular type or area) seem to have titles that begin with Secret to... OR Secrets Revealed..... If these authors are writing about so called "secrets", once they are out in the public, doesn't it go against it being a secret??

Nothing against the contents of these books, just why not call, "[Stuff] you may not know...." etc.

Something to think about.