Good overview of Crowley. Studied him, a fair amount, many years ago. Found him to be highly accurate, and very informed. My one quibble with him, is that he left everything open on the table as it were, much like leaving a loaded gun with a small child.
Have seen a number of people study Magick, and very few of them, able to actually work with it, over the long term. Their desires, appetites, and emotions tend to cloud their use of it, and it recoils on them, in time.