I had long ago discovered that when a word or formula refused to come to mind, the best thing for it was to think of something else: tigers, for instance, or oatmeal. Then, when the fugitive word was least expecting it, I would suddenly turn the full blaze of my attention back onto it, catching the culprit in the beam of my mental torch before it could sneak off again into the darkness. “Thought-stalking,” I called the technique, and I was proud of myself for having invented it.
