A certain writer ("past sixty, enjoying 'a certain renown'") strolls through the old book market in a Buenos Aires park: "My Sunday walk through the market, repeated over so many years, was part of my general fantasizing about books." Unfortunately, he is suffering from writer's block.However, that proves to be the least of our hero's problems.In the market, he fails to avoid the insufferable boor Ovando—"a complete loser" but a "man supremely full of himself: Conceit was never less justified." And yet, is Ovando a master magician?Can he turn sugar cubes into pure gold? And can our protagonist decline the offer Ovando proposes granting him absolute power if the writer never in his life reads another book? And is his publisher also a great magician? And the writer's wife? Only César Aira could have cooked up this witch's potion (and only he would plop in phantom Mont Blanc pens as well as fearsome crocodiles from the banks of the Nile)—a brew bubbling over with the question: where does literature end and magic begin?