Superman (1939-) #76

For the first time, Superman and Batman learn each other's secret identities when they meet on a cruise while trying to find a diamond thief.

Written By:
Bill Finger, Edmond Hamilton, William Woolfolk, Ben Galloway
Pencils:
Al Plastino, Curt Swan, Wayne Boring
Inks:
Al Plastino, Stan Kaye, John Fischetti
Cover By:
Win Mortimer