For anyone who wants to know more about the reasoning behind the publication of the Golden Dawn rituals and ceremonies, this is explained in depth in "What You Should Know About The Golden Dawn" by Israel Regardie (previously published as "My Rosicrucian Adventure").
For anyone who has read Regardie's lengthy introduction to "The Golden Dawn", then the style will be very familiar, as indeed will be some of the material (he quotes the same passages from Thomas Traherne in both, for example). This is not to say that you will have read it all before, but there will be a distinct sense of familiarity about it, which I personally found comforting, like reading a letter from an old friend.
However, the problem with this book is that it's almost entirely an apologetic. It was originally published two years before Regardie's "The Golden Dawn" came out, and was intended to defend his decision to go ahead with that publication and the breaking of his oaths. He was very right in assuming that he would receive a backlash from the leaders and members of the various Golden Dawn temples then active, but he was also very right in assuming that these same temples were on the threshold of abeyance.
Much of what is shared here is very familiar to us now, from both the exposition of the Order structure and syllabus (most notable of which is the Adeptus Minor curriculum, shared in depth [minus a document or two] in "The Golden Dawn") to the history of its founding, including the elusive Cipher Manuscript, Anna Sprengel, and Madame Horos debacle. This book has been quoted frequently (by the Ciceros, for example), and thus certain passages will be familiar, but it still sheds some light on matters that were not thoroughly explored in other books, offering much of the rumour that was around at Regardie's time.
This edition includes multiple additions which effectively double the size of the book. These include letters and short essays which can also be seen as apologetics, defending Regardie or dismissing the view of, for example, Ellic Howe. The highlights, however, are Mathers' manifesto, the letter he sent to the Adepti asking them to bow to his authority or face expulsion or demotion; and Yeat's manifesto, where he challenges the notion of forming into small groups, and asks if the Golden Dawn is to remain a magical order. Some other additions include a scan of Regardie's admission into the A.'.A.'., a postcard from Crowley which indicates that Regardie was initiated into the 9th Degree in the OTO, and various Hebrew tables, all of notable historical value (which shall settle the debate about Regardie's Thelemic grades once and for all).
I don't recommend this book for someone new to the Golden Dawn. I feel there is too much "venom" here to do any real good to someone who is unsure about the path; it may simply frighten them off. Regardie's criticisms of the founders and temple leaders are right and apt, but a less defensive historical account would do the new student much better before he or she reads this book. This is a book for those interested in history, and for anyone who wants to delve deeper into Regardie's notions of the Golden Dawn (where he, for example, reveals his knowledge that he knew well that the Adeptus Minor grade was technically in Yesod, not Tiphareth, with the previous elemental grades all in Malkuth). You won't learn any magick here, nor will you learn more about the structure, etc., of the Golden Dawn, which has been expounded in many places elsewhere. I would recommend the Cicero's "The Essential Golden Dawn" for anyone who really does want to know more about the Golden Dawn. This book by Regardie is best left until further down the path, when you have come to terms with the very real fact that most of the members of the Order, Adept or not, had very real flaws, and these colour the history of the Golden Dawn in very stark ways. This book offers a very intriguing insight into those flaws.
"What You Should Know About The Golden Dawn", by Israel Regardie: New Falcon Press (Fifth edition, 1983)