Last year, I met one of the world's first Iyengar yoga teachers. She attended B.K.S. Iyengar's first class in London, and was accredited at once, although she was an inexperienced housewife. When she started, hardly anyone taught yoga. To learn, you'd have to study in an ashram, or read an esoteric book. That's what Diana Clifton did. The tome that led her to Iyengar was also written by a woman - Indra Devi. Like Diana, she'd once been exhausted and frustrated, but wrote about how yoga changed her life.