Astanga, or sometimes spelled ashtanga Yoga is actually taught today by a man named Sri K. Pattabhi Jois, in Mysore, India.  He has brought astanga yoga to the west about 25 years ago and still teaches today at 91 years of age.  Astanga yoga began with the rediscovery of the ancient manuscript Yoga Korunta.  It describes a unique system of Hatha yoga as practiced and created by the ancient sage Vamana Rishi.  It is believed to be the original asana practiced intended by Patanjali.

The Yoga Korunta emphasizes vinyasa, or breath-synchronized movement, where one practices a posture with specific breathing patterns associated with it.  This breathing technique is called ujayyi pranayama, or the victorious breath, and it is a process that produces intense internal heat and a profuse sweat that purifies and detoxifies the muscles and organs.  This also releases beneficial hormones and nutrients, and is usually massaged back into the body.  The breath ensures efficient circulation of blood.  The result is improved circulation, a light and strong body and a calm mind.

There is a proper sequence to follow when practicing Astanga yoga.  One must graduate from one sequence of postures to move onto the next.  The Primary Series (Yoga Chikitsa) detoxifies and aligns the body, purifying it so that toxins do not block. The Intermediate Series (Nadi Shodhana) purifies the nervous system by opening and clearing the energy channels, allowing energy to pass through easily. The Advanced Series A, B, C, and D (Sthira Bhaga) integrate the grace and stamina of the practice, which calls for intense flexibility.  

It is best to find a trained and knowledgeable teacher to assist you through this discipline.  It is an intense practice that is rigorous, six days a week. You are guaranteed to find inner peace and fulfillment with each breath you take.