David Frawley of the American Institute of Vedic Studies is, in my opinion, one of the most erudite and informed yoga pundits on the scene today. I shall share with you a link to his writings on pratyahara, the fifth limb of Astanga yoga. If you have been practising with me this winter, you will know that pratyahara has figured in my teachings. I hope that this article enlightens you on its philosophical underpinnings. Om shantih shantih shantih.