While not all of his books are specifically focused upon Freemasonry, half a dozen include Freemasonry in the title, and in a few more the subject of Freemasonry more than touched upon. One has to note that his books relating to Rosicrucianism are also by default related to the subject of the craft.
In The Mysteries of John the Baptist, he remarks that 'there are two principle groups of people for whom John the Baptist has significant spiritual meaning, though in the case of Freemasons, I should say a group for whom John ought to have spiritual meaning; Masons have mostly forgotten why they were once "St. John's men."' In Freemasonry: The Reality, he discusses what he views as the "real meanings in the now completely misinterpreted rituals and symbols of the craft."
He also has the knowledge and vision to focus on the deeper truths and to describe them in remarkably clear ways, such as when in his work on Ashmole, The Magus of Freemasonry: The Mysterious Life of Elias Ashmole--Scientist, Alchemist, and Founder of the Royal Society, he cuts through the acquired ignorance of a few hundred years, and notes that "the adjective speculative generally referred to an occult activity, or one that involved mathematics or imaginative projection: that is, conjuring. We have all at some time or another "conjured up an image." The earliest English masonic catechism, in answer to the question "How high is your lodge?" gives the answer "It reaches to the heavens." The lodge was an imaginative projection, "conjured up" by its members to embody a center of the universe."
His other works of interest to Freemasons include The Golden Builders, an essay entitled Aleister Crowley and the Yezidis which is included in the volume entitled Aleister Crowley and Western Esotericism, edited by Henrik Bogdan, and the book which first drew him popular attention, The Gnostics.
If you are serious about Masonic education, take my advice. Give Albert Mackey a pass and read Churton first.