The sales manager of the biggest book store for ten blocks cannot be deceived in a customer. And he knew, of course, that, as a professor, I was no good. I had come to the store, as all professors go to book stores, just as a wasp comes to an open jar of marmalade. He knew that I would hang around for two hours, get in everybody's way, and finally buy a cheap reprint of the Dialogues of Plato, or the Prose Works of John Milton, or Locke on the Human Understanding, or some trash of that sort.