This book traces the developments in the yoga tradition that has led to the strongest yoga tradition practised in the world today, from Krishnamacharya to Pattabhi Jois' Astanga yoga system and the Iyengar system. The spread of these yoga systems all over the modern world is unparalleled in the history of yoga; it partakes of the nature of a mass movement. The introduction traces the development farther back by looking into a history of asanas itself, garnering evidence from different periods in Indian history and relating this to the basic texts of yoga philosophy. The book requires us to view the history and development of yoga from an entirely new perspective. The introduction centres around a translation of the yoga section of the Sritattvanidhi, the oldest text available at present substantiating a developed asana practice. This text written in the 1880s, foreshadows our own period.