In this erudite yet practical book Professor Cheng shares the secrets of his lineage and takes us to the heart of T"ai Chi Ch"uan, presenting it as a martial artm a medicine, and a means of exercise and self-development. With examples from anatomy and phyics, he demonstrates precisely how the postures and moves work, internally as energetic principles, and externally on opponents. Professor Cheng always emphasizes that disease (like an attack from an opponent) is an opportunity for training. The practitioer of T"ai Chi Ch"uan may serve as his (or her) own doctor and, likewise, as the physician (or trainer) of an attacker. This special text includes: -Thirteen essays on his insights into T"ai Chi Ch"uan. -Oral secrets from his teacher, Yang Cheng"fu. -Qestions and answers giving his commentary to the classics. -Descriptions and mechanics of push-hands, San Shou, and Ta Lu. -Prefaces by both Madame Cheng and Bejamin Pang-Jeng Lo.