My wife wants to tidy the house before she dies and I want to catalogue my books—not that there is any point in doing so, no one wants books these days and it is difficult (so I am told) even to give them away. Fortunately, our respective tasks are so Herculean that, on the assumption that a sense of purpose lengthens life, we have many years ahead of us. As I range my books, I had quite forgotten the existence of many of them. The problem is that, instead of proceeding with my task, I sit down to read them,…