On a warm, early-summer evening last year, a crowd of adolescent girls squeezed together on folding chairs in the rare-book room of the Strand bookstore in New York City. Hushed chatter filled the space as they waited for the sold-out event to begin. “Just think,” a teen whispered to her friend, “when she walks in, we’ll be breathing the same air as her.” It’s the kind of comment usually heard in the vicinity of pop stars and actors.