Regardie, Israel. The Golden Dawn: A Complete Course in Practical Ceremonial Magic. St. Paul, MN: Llewellyn. 1986.
I'm going to try something of a new kind of entry for a while: Comments on various works that may be of interest to Pagans, Wiccans, people interested in magic, and more. These comments are intended to introduce a book to a broader audience who may have heard of it but haven't read it. With that in mind, there are several things that these comments are not: They are not scholarly book reviews that attempt to comprehensively address the arguments of the work and all its relationships to the existing literature. Hopefully some of that sort of awareness will be included - so that someone who reads my comments would be better informed without still having read the book itself - but these are going to be briefer and aimed at a nonspecialist audience. For that audience, these comments are still not the kind of book review that tells you whether it's a "good" book or a "bad" book. I may occasionally excoriate a truly abysmal work for the fun of it, in general I want to tell readers who might want to read this book and why, and what readers will find or not find within it. It's up to you to use that information to figure out if it's a good book for you and for your interests and purposes.
I will especially note that Regardie's work is a compendium of a significant portion of the foundations of modern Western magic, and it would take a chapter-length review to do it full justice, so everything I said above about limitations applies to this entry with especial force.
Regardie's Golden Dawn is a single volume reissue of an earlier four volume set, and this weighty paperback is the most common way for people to get their hands on Golden Dawn material today. This is not Regardie's original work; he took the Golden Dawn materials that had passed down to him and edited them into a sensible order, and incorporated many documents circulated within the organization and commentary of his own, but he did not rewrite it from scratch. It begins with the basics of the Golden Dawn system, containing the knowledge lectures and intricately detailed scripts for the rituals, then goes into a wide variety of related magical techniques, including divination, scrying, and others that may have been taught and practiced within the Golden Dawn but were not always directly related to the initiatory structure.
The material retains a distinctively turn-of-the-1900s style, including the sparse outline structure used in many Golden Dawn documents that would have been supplemented with additional personal teaching. The knowledge lectures are in this telegraphic outline form, and someone studying them today would need to do more research to begin to understand the brief mentions included there. On the other hand, the rituals are written out in great detail, and several of the included documents are Regardie's commentary on the rituals or drawn from teaching materials on the meaning of rituals and how to carry out some of the magical procedures. Although Regardie tried to make this interconnected mass of material sensibly organized around the Golden Dawn's approach, this book is not going to be an easy reference for someone who wants to try to find a single piece of teaching or ritual.
On the other hand, for those who do want to study the corpus of the Golden Dawn in its original context, this edition is much more relevant than the cypher manuscripts. There are other books that have sought to release copies or transcriptions of the cypher manuscripts; those are of interest to historians and people who really want to trace the exact origins and evolution of the magical system; but if you want to know how the Golden Dawn functioned, and what the rituals were like, in at least some forms and some times, Regardie's text is the book you want. For example, I especially appreciated the meditations that are given for each of the first four Elemental degrees, because they summarized an approach to the Element and communicated it to me much more than even the description of the ritual.
Any interest this book holds for a broader audience, beyond people working in Golden Dawn type systems today, lies in its historical value. The Golden Dawn was a seminal source for the transformation of Western magic in the last century, and its influence is not to be underestimated. If you want to know where the Watchtowers language of calling the quarters comes from, this is the key link between its obscure Elizabethan origins and Gardnerian ritual. For someone like me, it's fascinating to see what this older ritual looked like and how it has changed over time. On the other hand, someone who identifies as basically Pagan or Wiccan today and is not directly involved in Golden Dawn type work will probably not want to lift a lot of material from here directly. Part of understanding the Golden Dawn includes grappling not just with its ceremonial nature, but also its deep roots in esoteric Christianity and mystical Kabala, such as that used in the Lesser Banishing Ritual of the Pentagram.
For those who are interested, it's also fascinating to see some of the pieces presented in a non-Thelemic context, since a lot of current familiarity with things like LBRP came down through Crowley. There's also the opportunity to rediscover some magical techniques that are rarely used today, such as geomantic figures. Finally, there is a ton of important material here for understanding the origins and development of Tarot. The origins of the Rider-Waite-Smith deck come directly through the Golden Dawn; but even more than that, Tarot was intertwined with the whole rest of the Golden Dawn system, having intricate connections to astrology and Kabala. Although the language is grandiose and often opaque (can you guess which card is "The Rose of the Palace of Fire"?), if you want to delve into these possible connections, going back to this source is the place to get it all.
Overall, Regardie's compendium can be a paradox: nearly impenetrable to the casual reader, seemingly outdated and irrelevant, for those who have the interest and the patience to immerse themselves in it, it is fascinating and invaluable.