The Canon was instituted by the ancient theocracies as a standard in music, architecture and all other arts. Even after the decline of the old world order and of the canonical standard, knowledge of the Canon was preserved in the mystery schools of Greece and Alexandria, and in the tradition of masonic and other craft guilds.
One of the most revolutionary books of the late 19th century, The Canon owes its high reputation to the august literary style of its author, as well as to its remarkable contents. Its strong influence on modern mysticism was acknowledged by Aleister Crowley and F. Bligh Bond among others, and has long been a prized item in the library of the discerning mystic.