The contents of the present book form the theme of the discourses which the Swamiji delivered for seven days during the Sadhana Week held at the Headquarters of the Divine Life Society, in the year 1973, before an audience of seekers of varied endowments and differing capacities on the path of spiritual practice. Hence, the lectures bear, naturally, an informal and personal touch of the teaching style, and this also explains the conversational accent maintained throughout, rather than a stricter form of expression usually associated with a deliberately written text.