Sri Aurobindo's principal work on yoga.

In this book Sri Aurobindo examines the traditional systems of yoga and provides an explanation of certain components of his own system of integral yoga. There is an Introduction, "The Conditions of the Synthesis", and four parts: "The Yoga of Divine Works", "The Yoga of Integral Knowledge", "The Yoga of Divine Love" and "The Yoga of Self-Perfection". The material was first published serially in the monthly review Arya between 1914 and 1921; the introduction and first two parts were later revised by Sri Aurobindo for publication.