The Mandukya Upanishad is noted for clearly enunciating a method of approach to Truth that we come across in the Upanishads alone in the whole of the world’s philosophic literature. The method consists in the analysis of the three states of waking dream and deep sleep which are common to all men. Through a study of these states, a way is pointed out even for those who are not willing to accept any theological presuppositions to form the necessary intellectual background for cultivating the higher life.