The definitive work on the famous Hermetic Order of the Golden Dawn.
Very briefly, the GD was a late XIX century England (victorian-edwardian) metaphysical initiatic-ritualistic organization congregating a wide eccletic corpus of mystical, occult and magic traditions from every continent. Its theoretic basis was the well-documented metaphysical traditions from the middle-east (Chaldean, Helenistic-Egyptian and Jewish or Astrological, Hermetic and Cabalistic) over which a wide number of concepts from many other disparate sources were added in a seemingly coherent "package". An interpretation of the latin Tarot deck was considered a core "book of lore". The grading system was based and expanded from Masonic and Rosecrucian traditions and an emphasis was made on lone meditation with well defined and very "graphic" magical rituals, fancy dresses and impressive collective ceremonial ritual shows which obligatorily marked the progression inside the Order. A series of "temples" were founded in the UK (1st was Isis-Urania in London) and abroad but keeping a very centralized monolithic organization.
Mr. Regardie was a late witness of the (already decadent) Order lore and rituals and managed to salvage most of it for posterity in this huge book (originally in two volumes).
Many Golden Dawn concepts were incomplete or inaccurate certainly due to dubious sources, convenient adaptations and incomplete studies. A minor example: as any latin subject knows (and calls them when playing any card game) historically the correspondence between Tarot suits and French-inspired modern ones is swords-spades, coins-diamonds (not clubs as in GD), sticks-clubs (not diamonds as in GD) and cups-hearts.
From the GD "tradition" a myriad of brotherhoods, orders and movements derived and many more certainly will come to be. Most of modern so-called "new-age lore" was, directly or indirectly, inspired on it. The two (undeservedly) most influential modern tarot decks (Rider-Waite-Smith and Crowley-Toth) were created loosely based on the GD's creed and the majority of modern decks simply follows them.
Recommended to every occult-lore buff and historian. ( )

This got me interested in Thelema. Wonderful reading, tons of information from a "Christ-ian" point of view. I had this book a long time ago and lost it a few years later, have yet to buy it again. Granted, most of the rituals in here are not for the Thelemite, but it does the basic structure and knowledge of the system which Aleister Crowley reworked to become the A.'.A.'. It also tells of alchemy and some stories surrounding the philosopher's stone. Note that that the ankh (soul symbol) is Greco-Egyptian, not only similar to the Venus glyph but also the sandal-strap of Hermes. Many of the teachings are Greek Gnostic and Egyptian, being a syncretic system. And I loved the tables for the planets, which are a nice complement to those in Liber 777. ( )

Classic book supposedly revealed against the rules of a secret society which practiced rituals and had levels of training based on ancient paganism. ( )

not mine, and he can come get it from the shelf whenver he wants. one of the few books TheEx actually owns, it's just further proof that he's got his priorities all out of whack.