Swami Nityasthananda, a senior monk of the Ramakrishna Order, who served as an Acharya at the Training Centre for Brahmacharins at Belur Math, has made a deep study of the subject based on the Shastras including Patanjali Yoga Sutras, Bhagavad Gita, Yoga Vasishtha, Vivekachudamani , Srimad Bhagavatam etc. and the works of Swami Yatishwarananda, Sri Aurobindo etc. as well as the Western Psychology. This was brought out serially in the Prabuddha Bharata and has been thoroughly revised by the Author for this publication.