>>satan boo boo occult
"occult" is a broad as fuck term that refers to those UNKNOWN fields of science, it doesn't necessarily relates to "the devil".
Manly P Hall simply describes what he has experimented and IMHO it has much value to offer. Whatever you will learn from him will be a tool (just as a fucking hammer or a gun) that is not good or bad per se and you can use it for whatever fucking ends you may.