The world has been obsessed with superheroes since at least 1938, when DC Comics launched Superman. Since then, like Spiderman, Captain America, Wonder Woman, and the Fantastic Four, Superman has been— with uncommon strength and virtue—a leading superhero archetype. The popularity of superhero comics is cyclical, often surging during war, perhaps why they are flourishing once again. The Incredible Hulk, Batman, and Iron Man battle evil in Hollywood this year. This month, the Metropolitan Museum of Art in New York opens “Superheroes: Fashion and Fantasy,” an exhibit that celebrates their glamorous haute couture…