“Do you ever indulge?” Alan Greenspan, then in his early nineties, asked with a twinkle in the eye. We were both flagging — it was four in the afternoon, and we had been laboring since nine — and I replied, flustered, that I might have done a bit as an undergraduate, but those days were over. The former Federal Reserve chairman immediately got up from the large table where we sat, walked over to his desk with a surprisingly jaunty step given his back problems, and produced a slim package wrapped