Dismissed for decades as juvenile entertainment, comic books had by the early 1970s come of age as America's “native art”: taught on Ivy League campuses, studied by European scholars and filmmakers, and taken up as a new generation's cultural critique of American society. The cultural regeneration of the comic book was made possible by the revamping of a key American fantasy figure, the superhero, from a transparent champion of the national interest to a genetic and species outcast mapping the limits of the human. This refashioning was most visible in the invention of the “mutant superhero”—a figure popularized in Marvel Comics's acclaimed X-Men series—whose genetic difference from humanity positioned the superhero as a cultural outsider akin to racial, gender, and sexual minorities struggling for political recognition in the post–Civil Rights period. In this essay, Fawaz theorizes the concept of “popular fantasy” to describe how tropes of literary enchantment are deployed to make sense of emergent real-world social and political relations. Through a close reading of the X-Men in the mid-to-late 1970s, Fawaz shows how the comic book visually absorbed the cultural politics of the women's movement and the gay liberation movement to figure “mutation” as an expansive form of cultural difference that wedded fantasy to the ideals of radical politics. By linking the fictional category of mutation to lived categories of difference, the X-Men series produced a mainstream popular fantasy that legitimized and helped shape readers' inchoate affective investments in antiracist and antisexist ideals in the 1970s.