Justice League of America #125

Two-Face crashes the Justice League's roster in this eye-catching December 1975 issue, with the dual-natured villain looming large in the foreground — his coin mid-flip — while Superman, Green Lantern, Hawkman, Aquaman, and a lightning-fast Flash react with visible alarm. The cover's speech bubbles ("Have you all freaked out letting Two-Face join the JLA?") perfectly capture the audacious premise, and Ernie Chan's bold linework gives the whole scene a wonderfully tense energy. It's a delightfully off-kilter concept for "The World's Greatest Super-Heroes," and one that makes it very easy to flip straight to the first page.