Bellur Krishnamachar Sundararaja Iyengar (14 December 1918 – 20 August 2014), better known as B.K.S. Iyengar, was the founder of the style of yoga known as "Iyengar Yoga" and was considered one of the foremost yoga teachers in the world.
He has written many books on yoga practice and philosophy including Light on Yoga, Light on Pranayama, and Light on the Yoga Sutras of Patanjali. Iyengar yoga classes are offered throughout the world. Iyengar was one of the earliest students of Tirumalai Krishnamacharya, who is often referred to as "the father of modern yoga". He has been credited with popularizing yoga firstly in India and then around the world.
Students often ask me what kind of yoga I practice, as there is an immense amount of confusion regarding the many styles of yoga. I reply that most yoga in the west that is taught is Hatha Yoga. Yoga that is concerned primarily with Asanas (postures) and Pranayama (Yoga of the breath). The differences with the Iyengar style are;
The importance of alignement in the postures and in the space
The use of Yoga props to help to achieve a "better" posture
The progression in learning the postures. i.e. standing postures are normally taught first, followed by sittings, forward bends, twists and backbends. With inverted postures starting simply and becoming more challenging.
The other reason why I have always practiced and teach this form of yoga is that there is a strong element of bringing the consciousness to the body in order to self correct and help with any nagging aches and pains.