Bellur Krishnamachar Sundararaja Iyengar was born December 14th. 1918 in India and has been teaching yoga from the age of 17. He has been an innovative and exacting teacher for 60 years and there are today 180 Iyengar Yoga Institutes in 40 countries. Internationally recognized as a leading authority on hatha yoga, B.K.S. Iyengar has established the relevance of yoga to the treatment and cure of many illnesses and stress-related conditions.

Iyengar has received many prestigious awards, including Doctor of Science from the United Nations Charter for Peace, Man of the Year in Yoga Education from the American Biografical Institute and the Puna Swasthya Award from the World Federation of Societies of Holistic Medicine. His books include classics such as Tree of Yoga (1993), Light on the Sutras of Patanjali (1993), Light on Yoga (1995) and The Illustrated Light on Yoga (1995).

B.K.S Iyengar has systematized over two hundred asana and pranayama techniques and has discovered the anatomical principles on which hey are based. In the asanas each part of the body have to be positioned in their correct places, so that each individual part as well as the various psychological systems may function to their best potential. Minutiae of the postures are explored to penetrate remote anatomical layers of the body. B.K.S. Iyengar has evolved the therapeutic application of the postures. He has devised methods of modifying the postures for maximum benefit of patients with disabilities. Leading members of the medical profession in India and elsewhere recognize his intimate knowledge the body and his explanations of pathology from the yogic point of view. He is known as an expert in treating medical problems.

Any common physical ailments and defects, including chronic disorders, can be improved by the practice of yoga postures. They work on specific areas of the body such as the joints, the liver, kidneys, and heart. The movement and extensions in the postures, including the positioning of the inner organs in the inverted sequences, have a profound effect on how they function. The body is oxygenated and filled with healthy blood, decongested and rested. Stamina, lung capacity, heart performance, muscle tone, circulation and respiration all improve.

GROUPS OF ASANAS AND EFFECTS
There are postures and cycles of postures that give a variety of different effects: stimulating, calming, energizing, building stamina or concentration, promoting sleep, internally soothing, and so on.

There are more than 200 asanas which can be divided into several main groups.

		Standing asanas (utthita trikonasana - triangle, virabhadrasana - warrior) They strengthen the leg muscles and joints, and increase the suppleness and strength of the spine. The spinal muscles and inter-vertebral joints are kept mobile and well-aligned. The arteries of the legs are stretched, increasing the blood supply to the lower limbs, and preventing thrombosis in the calf muscles. These asanas also tone the cardio-vascular system. It is the most important group for beginners as it prepares ground for further practice;
		Inverted asanas (salamba sirsasana - headstand, salamba sarvangasana - shoulderstand) These asanas have a drying effect on the pelvic and abdominal organs, while vital organs like brain, heart, and lungs are flushed with blood. According to Hathayoga Pradipika, Salamba Sirsasana (headstand) is the king of asanas, and Salamba Sarvangasana (shoulderstand) the queen of asanas. The health of ones body and mind are greatly enhanced by the practice of these two asanas.
		Back bends (bhujangasana, urdhva dhanurasana) These asanas stimulate the central nervous system and increase its ability to bear stress. They help to relieve and prevent headaches, hypertension, and nervous exhaustion. They stimulate and energize the body, and are invaluable to people suffering from depression.
		Twists (bharadvajasana, mariciasana) In twists, the pelvic and abdominal organs are squeezed and flushed with blood. They improve the suppleness of the diaphragm, and relieve spinal, hip, and groin disorders. The spine also becomes more supple and this improves the flow of blood to the spinal nerves and increases energy levels.
		Forward bends (janu-śirsasana, paschimottanasana) In these asanas the abdominal organs are compressed. This has a unique effect on the nervous system: as these organs relax, the frontal brain is cooled, and the flow of blood to the entire brain is regulated. The sympathetic nervous system is rested, bringing down the pulse rate and blood pressure. Stress is removed from the organs of perception and the senses relax. The adrenal glands are also soothed and function more efficiently. Since the body is in the horizontal position the heart is relieved of the strain of pumping blood against gravity, and blood circulates through all parts of the body easily. Forward bends also strengthen the paraspinal muscles, inter-vertebral joints, and ligaments.
		Sitting asanas (baddha konasana, virasana, padmasana) All sitting asanas bring elasticity to the hips, knees, ankles and muscles of the groin. These poses remove tension and hardness of the diaphragm and throat, making breathing smoother and easier. They keep the spine steady, pacifying the mind and stretching the muscles of the heart. Blood circulation increases to all parts of the body.
		Hand balances (mayurasana - peacock, bhujapidasana) These asanas strengthen arms and wrists while exercising abdominal muscles, they bring feeling of lightness in the body;
		Reclining asanas These are restful poses which soothe the body and refresh the mind. They help relax the body and strengthen the joints. They give the body the required energy for the more strenuous asanas. Reclining asanas prepare you for pranayama.