I only recently acquired this book because it has been hard to come by until it was republished last year. Linden briefly describes various ritualistic practices regarding "the Genii of the 22 Scales of the Serpent and of the Qliphoth" as outlined in Crowley's Liber CCXXXI. These rituals center around the "shadow tarot" which is an extension of Kenneth Grant's interpretation of these sigils in Nightside of Eden. Linden suggests Linda Falorio's Shadow Tarot deck for use or to create your own. The rites themselves are fairly simplistic with the only requirements being candles, a few incenses (usually Lunar) and the deck/sigils. Every now and then an athame, bowl or large mirror is required but not for most. Most of the practices described seem geared towards creative visualizations and atavistic resurgence but I have not tried anything from this book yet for a couple of reasons.
First, I am somewhat at variance with it due to the fact I am not a beginner. Had I had this book a few years ago it would have made my own approach a little easier and I might have gone about it in much the way Linden outlines but I was on my own and developed my own personal Oneiric methods based on a combination of theories and peripheral practices primarily from Crowley, Spare and Grant with heavy doses of Lovecraftian elements to create the kinds of moods for such endeavors. Other than my own uses of Spare's "death posture" at times, the sigils and the Thoth tarot, my practices were not objective in this physical ritual setting at all. They took the form of semi-pathworkings almost entirely in the dream realm with other practices suggesting themselves along the way based on information gleaned from the Interface. Almost by accident I did away with any attempt at defining a system early on. Becoming submerged in the Nightside does produce "tangential tantrums" as Grant calls them.
When I actually discuss the details of such matters some of you may notice my tendency to go into something a bit rambling and incoherent. That is the nature of everything to do with these Nightside currents. I feel a very personal connection to this area of work because it is the one thing magically that I have developed completely on my own from just reading obscure hints and references; I had to work on it. And probably for that reason it is also the one area of Magick that has had the most impact on me and has helped produce the most transformative and inspired "results". Some of those results can be read on my Occult Corpus blog in a more cleaned up form. That stuff comes directly out of personal dream imagery albeit reworked to make a little more sense to others reading it.
One personal benefit of this book for me though is that it provides me with a sort of model. I would like to develop my practices along similar lines as Mishlen Linden in order to better translate this stuff to others. That is the hardest part for me and is why I haven't discussed these things more openly. There is a part of me that feels that if I discuss it too plainly that it will banish the personal glamour that has gained power in my secrecy. But then I remind myself of the critics of Kenneth Grant's work who have accused him of revealing too much but in fact he has revealed nothing. It only appears to be revealed to the Initiated who actually understand what he's talking about. It took me quite a few years and firsthand experience to understand his work and now that I do there is nothing I can say that will reveal anything to anyone other than to those who already know.
My thread is obviously about a little more than just Linden's book and intentionally so. Having familiarized myself with Occult Corpus enough now, I don't feel that there will be a heavy amount of traffic engaging in a discussion of the uses of Crowley's Liber CCXXXI but I'm willing to give it a shot.
Another helpful book on this subject is Paul Hughes-Barlow's Tarot and the Magus. I came upon his book well into developing my own practices as well but noticed a lot of seeming similarities between what he describes regarding Liber CCXXXI and my own dreamworkings. He also uses the Thoth deck like I do.
In my opinion, Liber CCXXXI is the closest thing to a more traditional grimoire that Crowley wrote and I'm not so sure he intended it as such. It is a very powerful book for evocation when approached in the more peripheral way Grant suggests in Nightside of Eden.
I have always found it curious that in Israel Regardie's preface to Gems from the Equinox he has this liber in a group of which he says the following: