Suppose you were standing on the stairs outside the New York Public Library, beside Leo Astor or Leo Lenox, who gaze with serene, marbled regard across the exuberant pandemonium of Midtown Manhattan. Suppose, also, you were to ask the panoply of patrons passing by to name the fictional character who best captures the essence of capitalism. Chances are, the names you’d hear most often would be of miserly or unscrupulous figures—Dickens’ unredeemed Ebenezer Scrooge, for example, or Gordon (“Greed is Good!”) Gecko, from the movie Wall Street. Even in December, no one heading up to the Main Reading Room is...