Once, he had graded papers. People make jokes about a red pen, but it had been standard, back in those days, and the students hadn’t argued. The red, like the robe of an inquisitor, had meant authority. He was a polymath, teaching history and mathematics both … a noted expert in the history of mathematics … and he’d been good enough at his work to enjoy it. But it had been waiting, and it had never come. Not once, in 30 years, had he felt the electric shock that comes with a student standing up and rebelling for the sake of truth. They had rebelled, a few of them, the brave ones, the