Kurt Koch was an expert of his time on all things “occult”. He was a devout Christian, and wrote many books not only to sound the alarm about people becoming involved in spiritism, but also to educate people on the things of the occult so that they could be avoided.
This is one of those books. In it he details many topics in order to educate Christians about the devices of Satan so that we can avoid them (to be forewarned is to be forearmed). He covers topics such as: astrology, black mass, drug abuse, fortune-telling, hypnotism, magic, pornography, yoga and many other things.
I find Kurt Koch to be a reliable source of information on the topic of the occult. He had a sincere, well-grounded belief in Jesus, and did not exaggerate or tell stories for shock value. His purpose was to educate and warn people of the danger of occult activity which even in the 1970’s and prior was already massively infiltrating society and the church (and it has only gotten worse in the decades since).
If this is a topic of interest for you, this is an author that is well worth your time.