The X-Men #90

Against a stark yellow background, John Buscema's cover packs an emotional wallop — the faces of Cyclops, Marvel Girl, Havok, Iceman, and their teammates contorted in anguish as a dark, shadowy figure looms at the center, all beneath the stark declaration "Professor X Is Dead!" The dramatic tagline — "Not a hoax! Not a dream! Not an imaginary tale! This is for real!" — gives the whole image an urgent, almost breathless energy that was rare for 1974 superhero comics. Roy Thomas, Don Heck, and George Tuska bring the interior story "If I Should Die...!" to this charged package, making it a genuinely gripping installment in the X-Men's early run.