Yoga means Union and the purpose is to teach the practitioner of yoga, called the yogi, how to achieve union or spiritual Absorption into the Supreme Absolute or God. The greatest classical text from the yoga school of Indian Philosophy is the Yoga Sutras of patanjali written in the 2nd century BC. Patanjali who popularly known as Maharshi Patanjali was a Great Sage and Philosopher who compiled 196 Yoga Sutras (aphorisms) that constitute the foundational text of Ashtanga yoga also known as Rãja Yoga. The book finds its comprehensive treatment of commentaries of our Great Saint and Social Reformer Swami Vivekananda on Yoga Sutras of Patanjali. He has made incisive explanation on it in a very simple and lucid way which one can easily understand the Eight Fold path of Yoga.