There is a wealth of information about Iyengar Yoga on the web. You can check:

• The BKS Iyengar Yoga Studio of Dallas is where George Purvis teaches when he's not doing workshops elsewhere in the country

• The Iyengar Yoga National Association of the United States certifies Iyengar Yoga teachers across the country. They also have online a biography of B.K.S. Iyengar, the founder of the Iyengar school of yoga.