by Robin Sloan When Mr. Penumbra's 24-Hour Bookstore was released, the New York Times ran a nice profile of me and the book, and to fit the book's themes, the reporter, Jenny Schuessler, decided we should meet not in a conference room, not in a coffee shop, but in a secret library. We convened on a rainy morning at the Grolier Club, a society of bibliophiles in New York City, where—in addition to chatting about Penumbra—we got a chance to see something special. There, spread out on a dark heavy table, waiting in a pool of lamplight, was a collection of "Aldines"—books made by a guy named Aldus Manutius circa 1500, back at the very dawn of printing. Manutius features prominently in Penumbra's plot. He also features prominently in the history of civilization, because his shop produced the first printed editions of the classics: Aristotle, Homer, Virgil, all those guys. I'd read plenty about Manutius, and I'd seen pictures of his books online. But I'd never seen one in person, and what I saw at the Grolier Club surprised me.