Recently I have been reading Perdurabo, a biography of Aleister Crowley, alongside various texts by him on magic, most of which are available online for free, legally.
I found this biography as well as his writings flawed in many ways from a Buddhist perspective, but quite inspirational nonetheless. He was a very intelligent man, who kept up with the findings of his age and read widely on different traditions as well. He actually had quite a good understanding of the general concepts of Hinayana Buddhism, due to his friend Alan Bennett, who used to be a ceremonial magician before becoming a Theravadin monk. He didn't understand Mahayana Buddhism that well, let alone Vajrayana, but that is also due to the limited resources in his time. He has an interesting prose style, though I don't care for his poetry.
His commentary here on a text by Blavatsky derived from Buddhism but mixed with her own Theosophical ideas is quite interesting.
Sometimes what he says is almost like Vajrayana PoV:The Adept may plunge into the work of the world, and undertake his daily duties and pleasures exactly as another man would do, but he is not moved by them as the other man is.
Despite his use of Qabalah, he never fell into the trap of realism, like most Qabalists do:We who accept the Law of Thelema, even should we concur in this doctrine theoretically, cannot admit that in practice the plan would work out; our aim is that our Nothing, ideally perfect as it is in itself, should enjoy itself through realizing itself in the fulfillment of all possibilities. All such phenomena or "point-events" are equally "illusion"; Nothing is always Nothing; but the projection of Nothing on this screen of the phenomenal does not only explain, but constitutes, the Universe. It is the only system which reconciles all the contradictions inherent in Thought, and in Experience; for in it "Reality" is "Illusion", "Free-will" is "Destiny", the "Self" is the "Not-Self"; and so for every puzzle of Philosophy.
Not too bad an analogy is an endless piece of string. Like a driving band, you cannot tie a knot in it; all the complexities you can contrive are "Tom Fool" knots, and unravel at the proper touch. Always either Naught or Two! But every new re-arrangement throws further light on the possible tangles, that is, on the Nature of the String itself. It is always "Nothing" when you pull it out; but becomes "Everything" as you play about with it,* since there is no limit to the combinations that you can form from it, save only in your imagination (where the whole thing belongs!) and that grows mightily with Experience. It is accordingly well worth while to fulfill oneself in every conceivable manner.
It is then (you will say) impossible to "do wrong", since all phenomena are equally "Illusion" and the answer is always "Nothing." In theory one can hardly deny this proposition; but in practice—how shall I put it? "The state of Illusion which for convenience I call my present consciousness is such that the course of action A is more natural to me than the course of action B?"
Or: A is a shorter cut to Nothing; A is less likely to create internal conflict.
Will that serve?
His training program for his students involved pranayama, meditation, and different ways for them to train their body, speech and mind to discover what he called their True Will.Well, now, before going further into this, I must behave like an utter cad, and disgrace my family tree, and blot my 'scutcheon and my copybook by confusing you about "realism." Excuse: not my muddle; it was made centuries ago by a gang of curséd monks, headed by one Duns Scotus—so-called because he was Irish—or if not by somebody else equally objectionable. They held to the Platonic dogma of archetypes. They maintained that there was an original (divine) idea such as "greenness" or a "pig," and that a green pig, as observed in nature, was just one example of these two ideal essences. They were opposed by the "nominalists," who said, to the contrary, that "greenness" or "a pig" were nothing in themselves; they were mere names (nominalism from Lat. nomen, a name) invented for convenience of grouping. This doctrine is plain commonsense, and I shall waste no time in demolishing the realists.
Anyway I have no intention of following Thelema and doing his exercises; everything he does I think Vajrayana offers as well, and in a much more complete and tested way. But I find him more relatable as a flawed, modern man pursuing his own spiritual path in a modern environment than e.g. tulkus who had a more supportive environment all around them. I mean I think "This guy is a modern guy living in an age of "rationalism", well-read in different fields and he can still muster the effort to do his spiritual practice; I have teachings that IMO go beyond what he knew so I should can put in at least as much effort as he did."
His reputation as a "black" magician is vastly overstated, partly because he himself loved the notoriety and also because cultural Christianity was stronger then. His magic is no more or less objectionable than that of different tirthika tantras.