Kim Acheson came through the door, red-faced and sweaty from the unseasonable heat, apologizing for being late. Acheson, recently returned from an adventurous attempt to hike the 2,600-mile Pacific Crest Trail, had just encountered the kind of unexpected problem inherent in being a double amputee: In this case, his gym used soap to mop the floor, which made it too slippery to walk on with his prosthetic legs. I assured him it was fine and asked my first question: “What made you want to hike the Pacific Crest Trail?”