When I have a piece of writing in mind, what I have, in fact, is a mental bucket: an attractor for and generator of thought. It’s like a thematic gravity well, a magnet for what would otherwise be a mess of iron filings. I’ll read books differently and listen differently in conversations. In particular I’ll remember everything better; everything will mean more to me. That’s because everything I perceive will unconsciously engage on its way in with the substance of my preoccupation. A preoccupation, in that sense, is a hell of a useful thing for a mind.