The following is adapted from a new chapter for the paperback edition of “The Fifth Risk,” which will be published by Norton in November.
I found Art Allen standing on the lawn just outside his front door, a few miles inland from some uninviting Connecticut beach. He was in his mid-60s, and a scientist — but a scientist with a man-of-action feel to him. He wore a Coast Guard Search and Rescue polo and a massive Fenix 3 GPS watch, and he had this snow-white Hemingway beard. Six canoes hung from hooks inside his garage, a scrum of mountain bikes leaned against the wall, and all looked as if they had a lot of miles on them. So did he.