The Joker (1975-) #7

Lex Luthor and Joker: rivals in their own right just as much as their adversaries are allies. But this time, things take a mind-bending turn when Luthor's genius and the Joker's madness switch!

Written By:
Elliot S! Maggin
Irv Novick
Frank McLaughlin
Cover By:
Ernie Chan