Why has music so often served as an accomplice to transcendent expressions of gender? Why did the query "is he musical?" become code, in the twentieth century, for "is he gay?" Why is music so inherently queer? For Sasha Geffen, the answers lie, in part, in music's intrinsic quality of subliminal expression, which, through paradox and contradiction, allows rigid gender roles to fall away in a sensual and ambiguous exchange between performer and listener. Glitter Up the Dark traces the history of this gender fluidity in pop music from the early twentieth century to the present day.