Theurgy, or the Hermetic Practice: A Treatise on Spiritual Alchemy
Edward John Langford Garstin (1893-1955) was a life-long student of the occult.  He was initiated into the Golden Dawn in the early 1920s and was a member of the Quest Society until its closure in 1930.  He wrote The Secret Fire, first published in 1932 and edited The Alchemical Writings of Dr. John Dee.