Health & Fitness: Exercise in Best-Selling Lesson 3:

All right, class, rest and review. First we learned that while you may have to sweat to write your fitness book, this is only a warm-up exercise. The real work is promotion, which you should do for as many hours a day as your body can stand. But what if, after all that effort, the book is still headed for terminal inactivity on the remainder shelf? Hear now the tale of Callan Pinckney, whose deep-muscle-exercise regimen hit best-seller lists an unheard- of 14 months after it was published.

The first 12,500 copies of Callanetics (William Morrow & Co.; $17.95) barely managed...