Tantra is an ancient science dealing with many different systems for increasing the speed of human evolution. It predates all of the world's existing religions, and provides the esoteric basis on which many of these religions were later based. Tantra provides practical techniques applicable by men and women of every temperament and spiritual level, and aims at turning every action of life into an act of sadhana, or spiritual practice. The practices included in this book are based in tantra, though many of them have been forgotten for thousands of years. The task of rediscovering them and putting them in a form which can be understood and practised by people of this age has been done solely by Swami Satyananda Saraswati, as his personal contribution to a civilisation searching for a deeper understanding of the basis of life.