“What is not, potentially, a quotation? The dullest instructional prose, with the right light thrown on it, can acquire the gleam of suggestiveness or insight. ‘Objects in the rear-view mirror may appear closer than they are’: that one has been appropriated many times. Whenever I take a plane, I am struck by “Secure your own mask before assisting others” as advice with wide application. And I have often found myself imagining ways of fitting tab A into slot B.”