It's very heavy into the occult. Most would have an easier time understanding them in Black Sabbath & Led Zeppelin Lyrics where reference of Crowley's work show up. Or if you look up Anton LaVey which I don't think will help with the understanding portion, but it's kind of where modern day Satanism derives from.
I have books by Lavey and Crowley and yeah you are right when you mention Crowley being referenced in records by late 1960's groups. Crowley was in vogue in the late 1960's due to the Beatles putting his picture on Sgt. Pepper's LP cover and referring to him as someone they "admired" and by the films of Kenneth Anger ("Lucifer Rising")
I'VE had it for years , and finally managed to get it to a workable place , but it's the small thoth ; i wouldn't even touch the large deck . there's something basicly wrong with that green plus the presence of the unicursal-hexagram ... it's easier to walk around a trap than to defuse it .
Yes i have read about him and many of his writtings. I study many religions and cults.
..................his TAROT deck is messed up too ...................