We are grateful to our revered teachers, B. K. S. Iyengar and John Friend, and many others for their patient teaching and spontaneous inspiration; to Diva Robinson and Denna Reilly, our co-models; Donal Holway and Julio Torres for their fine-sensed and reliably good judgment in doing the photography; Susan Genis, Bindu Wiles, Sally Hess, and Tova Ovadia for their discerning eyes and practical suggestions; Carol Stratten, Dr. David Palmieri, Dr. Allan Cummings, and Norman Brettler for their work and help with dynamic MRI studies; Mary Ann Dunkin of the Arthritis Foundation for all her help; Jill Bialosky and Evan Carver for unfailing trust and continued editorial support; our students and patients for all they have taught us; and our families for their articulate silence and kind forebearance while we were not there.