This seems like a confusing topic to me. Some people view him as an insane criminal with average intelligence; some think of him as a demented man with slightly above average intelligence; some say he's super sane and his a genius?
How smart is the Joker, really? Where does his true intelligence rank when compared to other comic book characters? Is it possible that he is a super genius (like Lex, Reed, Tony, etc.) who's extremely high intelligence resulted in his madness?
Joker intelligence feats and scans are welcomed. :)