Clarity and Consistency
The principal reason is that Troward had the happy gift of expounding difficult ideas clearly and simply, and the five books together seem to me to constitute a consistent philosophical system which removes the intellectual and emotional obstacles, interposed alike by atheists, theologians, and politicians, between the individual human being and the Eternal Principle of the Universe. Troward's synthesis of what we may call Christian Philosophy, Christian Science, and Christian Mysticism thus sets a high standard by which all other systems of thought may be evaluated.
Troward's main works are the Books numbered 4, 6, 9, 10, and 11.
I shall defer to another occasion consideration of Book 1, Natural Law in the Spiritual World, parts of which pose problems — particularly in reconciling Troward's interpretation of the status and role of Jesus with Drummond's more narrowly "doctrinal" view.
Book 2, Light on the Path, is an attempt to describe the characteristics of a highly advanced mystic.
Bacon's Essays, in Book 3 may be treated as short treatises on aspects of ordinary human psychology and political manipulation thereof.
Book 5, Myths and Legends of the Celtic Race, exemplifies the role of tradition as an essential contributory factor in cultural development.
Book 7, Unto Thee I Grant the Economy of Life, probably written more than three thousand years ago, constitutes conclusive evidence that the technological advances on which we pride ourselves have not been accompanied by any raising of moral standards, but rather the reverse.
Book 8, The Kybalion, is a highly concentrated treatise on Hermetic Philosophy, the kernel which Troward's own books expound and elaborate.
Taken all together in the light of Troward's insights into the mental substrate which underlies all thought, Books 2 through 12 pose no great difficulties for any monotheist, and probably not many even for atheists. I therefore commend them as providing a sound launch platform from which to embark on a personal quest for ever-increasing understanding of the individual's true relationship with the Universe of which he or she is a unique microcosm.
Freemasonry
Secondly, the emphasis in the Masonic Lectures (which determine the rhythm of the Ardue University 'curriculum') will shortly be moving from ethics and practical morality to consideration of the what history and tradition tells the classical scholar about the development of Western philosophy and religion. It is therefore desirable for the student to have access to Troward's work as representing what can reasonably be taken as the finest flowering of this strand of evolution, not only for its own sake but as a beacon to help navigate the sometimes tortuous currents of thought and circumstance by which it was arrived at. There are many hints in Troward's writing that he may himself have been a Freemason of high degree; at any rate, he was obviously thoroughly acquainted with many Masonic traditions and symbols.
Troward and the Ardue Temple Library
Finally, Troward's books provide the mortar by which the other works in the Ardue Temple Library can be usefully fitted together in an educational edifice.