Superman's Pal, Jimmy Olsen #70

From 1963 comes this delightful chapter in the friendship between the Man of Steel and his intrepid pal, with cover art penciled by Curt Swan and inked by John Forte depicting a tense confrontation: Superman reaches toward a glowing chunk of Silver Kryptonite while a red-haired Jimmy Olsen stands opposite him, speech bubbles teasing that this mysterious new variety will affect Superman in a way he'll "never forget." A colorful display of the various Kryptonite types frames the scene, and the cover's bold tagline — "Nobody… but NOBODY… will guess 'The Secret of Silver Kryptonite!'" — makes this one genuinely hard to put down without finding out what Jimmy's up to.