[inostia]

Interestingly enough there's also an occult-related book called The Secret Teachings of All Ages by Manly Hall (1928). That book is more or less an overview of esoteric beliefs in the West. Why was he fascinated in this stuff?

[codezero]

It may make sense if you couple it with the MKULTRA/influence material he also had as a way to understand his adversary and potentially influence them using their own dogma.