Ya know, when I first started with all the occult, mystical, magical mumbo-jumbo doings, *lol*, I was thrown down the rabbit-hole just like Alice... It made no difference that I welcomed jumping into it by challenging everything I had been previously taught, (whether educationally, religiously, socially, or politically), I was as lost as lost can be, *lol*... Alas, when it came to Crowley, well, the rabbit-hole looked positively sane compared to his writings, *lol*
Now, given that he was touted as both the wickedest man in the world alongside with being the greatest magician the world had ever seen, the question was begged: 'who WAS this guy?'
I read his stuff, along with other stuff (as Aeon418 has suggested), so I could put a dent in understanding Crowley's stuff... But the fact remained that I would not participate in any kind of ritual doings because I STILL did not know who this man WAS... until I read 'Little Essays Toward Truth'... that book was the 'AHA' for me...
Finally, I could see what he stood for and, in that sense, felt him to be a decent man in his heart even tho his words and deeds at times, (okay, many many times, *lol*) were reprehensible... ugh, how human of him, *lol*
In any case, it eased my own mind and heart considerably in continuing to plow thru Aleister's vebose egomania... Yet, it was, to me anyways, his acute hubris that brought him to the forefront of the general population's fascination with him and, therefore, occult wisdom... a good thing, in and of itself... Should he have been a mild-mannered genius, Thelema would be in the belfry along with the bats and no one the wiser to its existence...
The other book that so touched me was his, 'The World's Tragedy'... It's a play actually... but again, for me, gave me an insight into his heart... After all, I can only take so much 'brains', *lol*... Brains without Heart, to me, is like Power without Love... it just runs amok turning to cinders everything in its path including itself eventually... Which is why, I suppose, 'Love is the law, love under will', *s*...
I have to agree that everything I've read, and continue to read, other than Crowley helps me enormously in understanding him all the better...
As for Qabalah, I found two books that were invaluable to me regarding magick... Dion Fortune's 'The Mystical Qabalah' and Eliphas Levi's 'The Mysteries of the Qabalah: or Occult Agreement of the Two Testaments'