«No one has attempted, so far as I know, to classify the various Sufistic systems. It is not so difficult to do so when a key can be found to them. The best key is that four-foldness which manifests itself in all human character, endeavor, and work. Corresponding to the four-foldness of character delineated above, I shall now take the terms Life, Love, Light, and Law and say that Al-Ghazzali and Jelaladdin represent the first and, as a proof, point to their constant emphasis of will as being the dominant power of existence, and the prominence they give to moral worth. The type of Love, in the form of poetry and feeling, is represented by Hafiz and Jami. The third group is fully and completely filled by Shabistani, the author of ‹Gulshan-i-Raz.› It is Light, and its form is Philosophy, Truth, and Understanding. The last, the fourth, sums up in a measure, the three preceding, and is also a clearly defined group by itself. It is Law, Order, Unity, and Reality. There is more independence in it than in any of the others, because it is the nearest approach known in existence to Wholeness or Unity. It contains the opposites of existence, both cosmic and human, viz.: the protest of the Mystic and also his affirmation, and the new Hope he represents. «Omar Khayyam belongs to this fourth group. I do not say he alone fills it. But he exhibits that Independence and Protest which is the first and outward characteristic of it. He is also from time to time soaring into the realms of the Truth or Unity, in a way not found in any other Sufi poet or doctor. «Under the garb of the Mystic's favorite method of Doubt and Protest, the Sufi (Omar) pictures the process of the Awakening of the Soul. That is the purpose of the ‹Magic Shadow-shapes that come and go› in the Rubaiyat of Omar Khayyam. His pictures are sufficiently transparent for us to see The Reality Behind. «While so much is claimed for Omar, it must not be forgotten that it has not been said that he is the only perfect Sufi. It is not our intention to say or to intimate that. Omar is great enough when we attribute to him the office of an Awakener; not merely that of a John the Baptist, but the office of one who is himself full of the Awakening he preaches. Such an one is a unique character, and is truly an At-oner, one who heals all wounds and binds up broken limbs.»