If you thought the fitness craze was about being healthy, think again. Although Charles Atlas, Jack LaLanne, Jim Fixx, Jane Fonda, Richard Simmons, and Jillian Michaels might well point the way to a better body, they have done so only if their brands brought in profits. In the first book to tell the full story of the American obsession with fitness and how we got to where we are today, Jonathan Black gives us a backstage look at an industry and the...