Introduction to Tantra Sastra, by Sir. John Woodroffe (1865–1936) also known by his pseudonym Arthur Avalon, was originally published as the Introduction to his English translation with notes of "Maha Nirvana Tantra (Tantra of Great Liberation)".
In this book he gives an outline of Tantra Sastra for beginners. He was a British Orientalist whose work helped to unleash in the West a deep and wide interest in Hindu philosophy and Yogic practices. He is known as the father of Tantric Studies. His works on Tantra such as "Serpant Power, Shakti and Shakta, Garlanda of letters, etc" have remained very popular even after many decades.