Two thumbs-up. Great book, honest and insightful, inspiring, well written.
The author quoting a volunteer at the Western States 100 mile race: "Pain is the body's way of ridding itself of weakness." Quoting his track coach, "If it feels good, you're doing something wrong. It's supposed to hurt like hell." (Karnazes, p. 129). The author describes how he relished the pain and celebrated it.
15 miles will be nothing compared to what this guy has done.