We’re back to Ron Chernow’s recent biography of Mark Twain, the famous American who came and went with Halley ’s comet. I n Tw a i n’s dark world, there is no alt ruism. What looks like altruism, according to Twain, is just a more subtle form of self-interest. I challenge that view.It was residency, a time of life where you work, work and work, and you eat and sleep when you can....