The Indian Tantras, which are numerous, constitute the Scripture (Shastra) of the Kaliyuga, and as such are the voluminous source of present and practical orthodox "Hinduism." To the Tantra we must therefore look if we would understand both ritual, yoga, and sadhana of all kinds, as also the general principles of which these practices are but the objective expression. Of all the forms of Hindu Shastra, the Tantra is that which is least known and understood, a circumstance in part due to the difficulties of its subject-matter and to the fact that the key to much of its terminology and method rest with the initiate. The present translation is, in fact, the first published in Europe of any Indian Tantra.