Few books achieve the fond hopes of their authors and their admirers. This is just one that succeeds, making a genuine and profound contribution to the fields of biomechanics, orthopedics and rehabilitation. It moves with easy grace from any topic to its neighbor, shedding warmth and life to them all. As one who has experienced both the high and low points of medical writing and editing over several decades, I see in these pages a true work of genius. It deserves a very wide readership and enthusiastic application of its lessons. John V. Basmajian Professor Emeritus in Medicine, McMaster University Hamilton, Ontario, Canada