With irreverence, humor, and soul-touching candor, the former editor of Bicycling magazine explores the CrossFit phenomenon, the fitness revolution sweeping America, chronicling his experience "inside the box" and how he got into the best shape of his life.

Lifelong amateur athlete Stephen Madden decided to put himself to the test, physically and mentally, by immersing himself in the culture, diet, and psyche of CrossFit--the fast-growing but controversial fitness regime that's a stripped-down combination of high intensity aerobic activity, weightlifting, calisthenics, and...