Tales of Suspense #39 (March 1963)

Iron Man's debut, and a cover built around a question: "Who? Or what, is the newest, most breath-taking, most sensational super hero of all?" A strip of panels down the left shows the clunky gray armor being assembled piece by piece before the full suit stands in the middle. Credited to Jack Kirby and Don Heck, it captures the original gray suit, which turned gold in the very next issue.