Superman #175

This 1965 DC offering presents a wonderfully strange "Imaginary Novel" premise right on the cover: a grinning Superman shakes hands with a bald Lex Luthor, who is apparently offering to impersonate Clark Kent — complete with Kent's civilian clothes — while a silhouetted woman watches from the doorway. Curt Swan's pencils and George Klein's inks give the scene a breezy, good-natured energy that makes the wild concept feel entirely plausible within Superman's imaginative Silver Age world. Writer Edmond Hamilton's premise — Lex Luthor as Clark Kent's brother — is bold enough to earn the "Great Imaginary Novel" banner it proudly wears.