There are wonderful experiences to be found in the ancient schools of mysticism, among Sufis, among Yogis, among Buddhists also. The knowledge which has been given perhaps four thousand years ago is put in clearer language and explained better, and yet it keeps the beauty and characteristics of the whole tradition. And the beauty of mystical knowledge is this, that whatever school it may be of, and from whichever part of the world, that central theme of the knowledge of truth is one and the same.