From its early origins to Thelma and Crowley's Golden Dawn involvement, this book is a good introduction to the historical aspect of occult studies. Most of the occult studies focused on have western origins, so don't look for much detail of religions reaching the far east. The information builds off of itself and is compiled in a comprehensive manner, so it's better if you accept the book as a whole and don't just waste your time looking up the chapter on alchemy. Reading the whole work shows how the arts relate to each other. Richard Cavendish was an Atheist, and that fact is critical to understanding this book. As a secular person, Cavendish understood that the power of ritual was in its ability to focus attention and energy through the use of symbolic representations, and not in any alleged supernatural powers. This understanding is critical to Satanists and others seeking to use "low magic" (personal rituals) or "high magic" (public acts designed to create or direct opinions, attitudes, etc.). The ability to control others through the use of symbols (be they flags, images, words, religious icons or other objects) is a source of great power to the Satanist who understands the proper use and application of symbolic acts. Unlike Wiccans and other neo-pagans who make claims on par with other religions concerning their supposed "goodness", a "black magician" is honest enough to admit to himself (or herself in the case of a Witch) that the purposes of magic are to enhance one's own wealth, power, sex life, etc. and to bring about the destruction of opponents and those who would deny the needs and desires of a Satanist.