Book excerpt: Intended for anyone who wants rock-hard abs but needs help getting motivated, the editors of fitness authority Muscle & Fitness magazine have created a four-week plan that incorporates invaluable take-away strategies to get a firmer midsection. More than 50 exercises and full-color photos guide readers through the best ways to obtain a tight six-pack. Throughout the exercises informative tips and fast facts are included to ensure that each routine is executed in the safest and most effective manner possible.