This is not an easy book to read, but then, when it comes to the Qabbalah and the Golden Dawn, there are very few books that are. However, Regardie's book scores over some of the other Ceremonial Magic books out there because he was Aleister Crowley's secretary for a number of years. If you intend to study some aspect of the Golden Dawn, ceremonial magic, or the O.T.O, you will at some point run into Crowley's writings. Regardie has a good grasp on Crowley because of his long term personal experience with him, and also presents information in an easier to read manner.

Even so, despite being written in the sixties, the language is very much that of intellectual England between the wars, and can get a bit bogged down. Regardie does however cover some key truths in incredible clarity, and if you are intending to read his epic works on the Golden Dawn (The complete system of Magic, for example), I strongly recommend you take the time to read this first, to get a good overview and understanding of the reasons why things are done a certain way. Some of those reasons you may find surprising!