«Mahanirvana Tantra» by Arthur Avalon

The best known of the Tantric scriptures. It was translated by Sir John Woodruffe (under the pseudonym 'Arthur Avalon'), one of the few Indologists to gain direct access to this obscure and secretive branch of Hinduism. Framed as a conversation between the god Shiva and goddess Shaki, this text describes the chakra, or subtle energy structure of the human body, ceremonies, yogic practices and mantras for meditation, and a summary of the Hindu laws (dharma) regarding sexual behavior.

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." The Tantra Shastra is, in fact, and whatever be its historical origin, a development of the Vaidika Karmakanda, promulgated to meet the needs of that age. Shiva says: "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, O auspicious one! is given". To the Tantra we must therefore look if we would understand aright both ritual, yoga, and sadhana of all kinds, as also the general principles of which these practices are but the objective expression.