World’s Finest 88 (June/July 1957) hides it’s greatest draw from the cover, the first ever team up of Lex Luthor and the Joker.
Hamilton, Sprang and Kaye craft a fun little story here, but it’s largely a Luthor tale. They do form a partnership together, but it’s primarily about the mechano-men that Luthor has invented.
Superman and Batman both get publicly humiliated after stopping what appear to be crimes by the mechano-men, but are really legal uses of the robots. Superman stops one as they perform an underwater search, taking it’s place.
He hopes to find out what the Joker and Luthor are really up to. The villains figure out that Superman is one of the mechano-men, but are confident enough in their plan to let him stay.
And the plan was not a bad one, having mechano-men impersonate them during a big demonstration, while they use other to pull off a big robbery. But Superman spotted the extra sets of clothes, and figured it out first.
The story would lead not only to many more Joker/Luthor team-ups in this book, but to other pairings of Superman and Batman villains.