In my roundup of books of the year, I mentioned The Grand Canyon: Between River and Rim by Pete McBride (Rizzoli, £40), who trekked the length of the canyon with his friend Kevin Fedarko. I’ve just been alerted by the Twitter feed of The New Yorker to a piece the magazine published in September, by Nick Paumgarten, who was invited to join McBride and Fedarko — and found reasons to say no. From his summary of what they went through, it sounds as though he was wise…

On the trek, they each carried packs that averaged about fifty pounds, containing eight days or so of food, as much water as they could hold, and not much in the way of accommodations. They carried a plastic syringe to draw water from potholes in the rock. McBride carried just one camera, one lens, and a solar charger; on cold nights, he kept the batteries warm in his armpit. The temperature ranged from a hundred and twelve degrees Fahrenheit to five degrees. There were hardly any trails, save for those made by game. “Sheep shit was our G.P.S.,” McBride said. They climbed over a hundred thousand vertical feet. “We went through seven pairs of shoes, four ankles”—they each sprained both—“and two girlfriends” (both McBride’s). There were broken fingers, and surgery to remove a cactus spine. McBride, still a bull of a man at forty-seven, lost thirty-five pounds, and, just five days into the first leg, nearly perished of hyponatremia, salt depletion from over-hydration, which is the leading cause of death in Grand Canyon. Once the project was complete, he needed heart surgery.