Koons admits to reading the same books over and over again — regardless of the season. No Kindle for him, either. On his nightstand (or in his suitcase) are lots of Plato, Nietzsche’s “The Birth of Tragedy” and pretty much everything on Picasso. He also reads the art historian John Richardson and the philosopher John Dewey. At this very moment: “I’m currently reading a wonderful book my wife gave me of Manet’s letters,” he says.