One of the most enduring and beautiful aspects of Schuon's writing is the way he keeps pushing the reader back to a focus on essence and authenticity. He compels the seeker to realize that universal truth is consistent no matter what symbolic concepts we might utilize to describe that truth. This is one of the key ideas of Perennialist thought, yet like all deep truths, those who express it must use great caution in a world of multiplicity. Seyyed Hossein Nasr, himself a student of Schuon's, wrote the new introduction to this classic work, and discusses how Schuon for many years put off the idea of writing a book with the word "Sufism" in the title as he thought it would give a misconception of Sufism as being separate from Islam. "When we turned to him again and asked him why it was that he had now changed his view and decided to use the word Sufism as part of the title of his new book, he said that through all these years he had established the truth that Sufism was the inner dimension of Islam, and now he could deal with Sufism itself and the intricate factors that were involved in the formulation, exposition, and practice within this tradition." (intro, p. vii)
In the symbolic language of religion, and specifically of Sufism, Schuon calls it: "A crystal that captures the divine Light, refracting it in accordance with a language that is at once particular and universal." (xiv, preface). "For it is not a question of inventing truth, but remembering it." (xiv, preface)
Schuon's concern is twofold: to present Sufism in its esoteric significance as a function of Islam and to show how Sufism taps into the essence that is at base the ultimate reality beyond all religious forms. This idea of particular yet universal is in constant tension in his writings. "It follows from these considerations that God is the same for all the religions only in the divine 'stratosphere', not in the human 'atmosphere'; in this 'atmosphere' each religion has its own God for all practical purposes, and there are as many Gods as there are religions." (41).
In his portrayal of Sufism, Schuon spends some time illuminating formative and historical aspects of Islam itself. Particularly valuable is the way he describes Arabic rhetoric and therefore the nature of the written form of the Qur'anic discourse. The elliptical nature of the Qur'an is a direct product of its Arabic revelation and is profoundly beautiful in its layers of meaning. For the Westerner, however, this aspect of the Qur'an can be enigmatic, especially in translation. The Qur'an puts into words precisely what cannot be put into words, and is a sublime symbol of the particular yet universal. As it relates to the Western mind, Schuon compares it to reason, ultimately calling reason "a groping in the dark" (17), but a groping that is searching for something realized a priori. This a priori knowledge means that it "is not the mind that is groping, but the language" (17). Sufism as practice and method seeks to aid the believer in realizing and experiencing this knowledge, which at base is ultimate truth.
This knowledge which Schuon speaks of is veiled by various layers of modernity. Schuon's goal, and the goal of Sufism is to help the seeker remove these veils so that the soul is pure in its remembrance of the divine. This divine remembrance or "dhikr" is one of the most fundamental ideas and practices of Sufism. Schuon spends a great deal of time discussing what the pure invocation of the name and remembrance practices of Sufism mean in relation to the whole of Islam, to the Sophia Perennis and ultimately to the realization of higher spiritual truths. Schuon describes the Dhikr as "work in the highest sense of the word." (120). It is the most authentic work in the most authentic of esoterisms, which in the Islamic form is expressed in the teachings we have come to know as Sufism, and which here is expressed by a man who has lived, practiced and experienced these ideas for himself, and who spent his life passing on this spiritual lineage to everyone who knew him.