Iyengar Yoga, named after and developed by B. K. S. Iyengar, and described in his bestselling 1966 book Light on Yoga, is a form of yoga as exercise that has an emphasis on detail, precision and alignment in the performance of yoga postures (asanas).
The style often makes use of props, such as belts, blocks, and blankets, as aids in performing the asanas. The props enable beginning students, the elderly, or those with physical limitations to perform the asanas correctly, minimising the risk of injury or strain.
B. K. S. Iyengar learnt yoga from Tirumalai Krishnamacharya at the Mysore Palace, as did Pattabhi Jois; Iyengar Yoga and Jois's Ashtanga Vinyasa Yoga are thus branches of the same yoga lineage, sharing many of the same asanas. Iyengar began teaching yoga as exercise gradually, starting with individual pupils such as the violinist Yehudi Menuhin, whom he met in 1952; Menuhin's fame helped to propel Iyengar Yoga as a brand in the Western world.
A landmark was the publication of Iyengar's bestselling book Light on Yoga in 1966, describing over 200 asanas in "unprecedented" detail. The yoga scholar Andrea Jain called the book "arguably the most significant event in the process of elaborating the [Iyengar Yoga] brand". Jain and others have noted that the book's biomedical claims, such as of toning up various organs of the body, were attractive to its audience but were stated directly without any supporting evidence. Authorities such as the yoga scholar Elliott Goldberg have described it as the bible of modern yoga; the book has sold over three million copies, and has been translated into at least 23 languages.
Iyengar Yoga became an institution with the 1975 founding of the Ramamani Iyengar Memorial Yoga Institute in Pune, named in memory of his wife. A further major step was the founding of the first of many institutes abroad, the Iyengar Yoga Institute (IYI) in Maida Vale, London, in 1983. The old IYI building was replaced in 1994, and the new one was officially opened by Iyengar in person in 1997.