World's Finest Comics (1941) #88 CGC Graded 4.0
(W) Edmond Hamilton (A) Dick Sprang, George Papp, Fred Ray (CA) Curt Swan, Stan Kaye
Lex Luthor and Joker team up, creating nearly indestructible robots. Superman and Batman must track them down and deduce their master plan.***As of this listing (10/2019) there are only 30 copies of this comic that have been submitted to CGC grading.