Mommy is what the old girl’s husband calls her. And idea is a generous word for whim or flight of fancy, the kind of ill-considered impulse he’ll have often and won’t quit till he’s pulled it off (he almost always does, if barely) or failed (more rarely, but with flying colors). Not scheme or plan—God knows the old girl’s husband can’t be bothered with anything like a plan. “It just came to me,” he says. “I thought I’d run the marathon this year!” As if the race has been, in previous years, an option he just didn’t exercise. Such glee in his voice. As if of course the old girl will see it as he does. The best idea in the history of ideas. Right now they live in Chestnut Hill, in Newton, Massachusetts. So when her husband says “the marathon” he means the marathon: Boston, mother of all. Not counting Greece, of course—original but defunct. Not with his colleagues, either—men his age or older, with wives and kids and coronary issues of their own—but with his students.