Gr 9 Up—These excellent guides are primarily directed at adults, though interested teens will find them helpful. All four volumes make use of photos, diagrams, sidebars, and text boxes to offer well-written, step-by-step instructions to a variety of exercises and poses. Core Fitness contains 33 "core stabilizers," 30 "core strengtheners," three "cool downs," and 10 workouts, including an "Over-Fifty Workout" and a "Beach-Bod Bikini Workout." A well-toned adult models each exercise, and photos are accompanied by anatomical illustrations showing key muscles used. There are also sections on getting started and nutritional advice. Tai Chi has a longer introduction, which outlines the history and philosophy of this discipline. Yoga observes that along with a yoga mat, props such as blocks and straps can help beginners and more experienced students "improve their alignment and balance." Readers will also appreciate an icon index for cross-referencing. VERDICT Well-executed guides that will intrigue teens with an interest in fitness.