SN. Dasgupta

 "The Upanishads represents one of the most distinctive, types of mysticism that India has produced. The word "Upanishad" has been interpreted etymologically by Shankara to mean "that which destroys all ignorance and leads us to Brahman." It has also been interpreted to mean a secret or mystical doctrine, or a secret and confidential sitting. The Upanishads are mystical experiences of the soul gushing forth from within us; they sparkle with the beams of a new light;