"The end and aim of all science is to find the unity, the One out of which the manifold is being manufactured, that One existing as many. Raja-Yoga proposes to start from the internal world, to study internal nature, and through that, control the whole - both internal and external. It is a very old attempt. India has been its special stronghold, but it was also attempted by other nations. In Western countries it was regarded as mysticism and people who wanted to practice it were either burned or killed as witches and sorcerers. In India, for various reasons, it fell into the hands of persons who destroyed ninety per cent of the knowledge, and tried to make a great secret of the remainder. In modern times many so-called teachers have arisen in the West worse than those of India, because the latter knew something, while these modern exponents know nothing."

- Swami Vivekananda, "Introductory" (Dec 14, 1895, New York Vedanta Society), Raja-Yoga, Complete Works: Vol 1