The Indian Tantras, which are numerous, constitute the Scripture (Śāstra) of the Kaliyuga, and as such are the voluminous source of present and practical orthodox “Hinduism”. Whatever its historical origin, the Tantra-Śāstra is in fact a development of the Vaidik Karma-kaṇḍa, promulgated to meet the needs of this age. Śiva says: “O Auspicious One! For the benefit of men of the Kali age, men bereft of energy and dependent for existence on the food they eat, the Kaula doctrine is given.” — Mahānirvāṇa Tantra 9.12 If we would properly understand ritual, yoga and sādhana of all kinds, and also the general principles of which these practices are but the objective expression, we must therefore look to the Tantra. Yet of all the forms of Hindu Śāstra, the Tantra is least known and understood. This is due both to the difficulty of its subject matter and to the fact that the key to much of its terminology and method rest with the initiate. The portion of the Indian public that favors ‘reformed’ Hinduism admire Mahānirvāṇa Tantra for its noble exposition of the worship of the Supreme Brahman, and in the belief that certain of its passages absolutely discountenance the orthodox ritual. Nothing can be more mistaken than such belief, even though “For him who has faith in the root, of what use are the branches and leaves?” Anyone who reads the text will discover this. It is true that brahmajñāṇe samutpanne krityakrityang na vidyāte: “Knowledge of Brahman grows in the purified heart” — 7.94. The statement assumes the attainment of Brahma-jñāna, and the Śāstra says this can be attained, not by mere Vedāntik discussions nor prayer, but by the sādhana which is its main subject matter. The section of Tāntrikās who think Mahānirvāṇa Tantra is too restrained are also in error. For the design of this Tantra appears intended to conserve well-recognized Tantrik principles while securing them from abuse. Pārvatī says: Hitaya yane, karmani kathitani tvaya prabho Manyetani Mahādeva viparitani manave”O Lord, I fear that even that which Thou ordain for the good of men will, through them, turn out for evil.” — 1.67