This work dedicated to tantra, the oldest Hindu esoteric tradition, was written by the famous researcher of Indian culture, the author of the magnificent "Encyclopedia of Yoga" Georg Ferstein. Relying on tantric texts, the author gives an interpretation of the foundations of the philosophy and practice of tantra, emphasizing that many of its facets are especially valuable for those who are engaged in self-knowledge and seek to solve the problem of spiritual transformation. For a wide range of readers.