Those are excellent books, but Crowley's greatest fallacy, as far as I'm concerned, is that reading him can be like butting into a conversation about which you know nothing and are expected to follow. It could be said that he respects his readers a little too much (although once you get into things, he's a great teacher). None of those books are really for the laymen, and so it isn't surprising that you're missing vital information, through no fault of your own. Now, someone like Aeon can, and probably did (
) read those same books and didn't find them lacking, but I'm a normal person and like a bit more explanation.
First off, the best book to give you a general introduction is
Understanding Aleister Crowley's Thoth Tarot by Lon Milo DuQuette. You really need to get the basic vocabulary down, since it is evident it is missing (and again I'm not blaming you). That's the best book for it, and it naturally leads to other avenues of study.
I would recommend a firm base in Kabbalah, which you might already have, but if you don't, Dion Fortune's
Mystical Qabala is a very good book to start from, although there are many. After these two books, the self-referential Book of Thoth will seem much easier. No choice but to do some homework.