Published Jan 1971 by DC.
Cover art by Neal Adams. Superman Breaks Loose, script by Denny O'Neil, pencils by Curt Swan, inks by Murphy Anderson; A scientific experiment turns all the kryptonite on Earth to iron, as Clark Kent moves from newspaper to television journalism. Super-Turtle humor page by Henry Boltinoff. Jor-El's Golden Folly--The Fabulous World of Krypton, script by E. Nelson Bridwell, art by Murphy Anderson; Ignoring the jeers of his colleagues, Kryptonian scientist Jor-El experiments with using anti-gravity to aid in space travel.