We are fast becoming a nation of runners, the authors say, and more power to us. If perchance you hadn't heard that jogging and running are good for your heart, your digestion, your emotions, and your immortal soul, they spell it out in statistics, anecdotes, and biochemistry. In addition, every page of this large-format book is lined with marginalia--quotes, tables, or anecdotes about famous pros from Olga Korbut to Muhammad Ali. What's appealing about these is their balance of reason and nuttiness. The authors rightly argue, for example, that anyone who eats wisely shouldn't need vitamin pills. Yet they quote coaches and players who either swear by the pills or take them for a psychological boost. Then, too, one of the authors is a sportsmedicine doctor and runner, and he frequently confesses his own past idiocies as cautionary tales, including the time he took amphetamine and nearly died of heatstroke. There is a lot of interesting material here about diet, exercise, training, first aid (in most cases you begin with RICE: rest, ice, compression, and elevation); about working up to peak performance, preventing some of the most common complaints (pulled muscles, cramps, tennis elbow, etc.); and about choosing a doctor and learning that athletes may have very different measures on standard medical tests. If there is such a thing as an uncertain jogger, the book is a powerful sermon. It might even persuade the armchair sloth.