I only know vaguely about Aleister Crowley's work, I have the small red book (forgot the name). From the little I studied about it, it seems to send the reader in some potentially very weird directions. I prefer to stick with the white side of things, as playing too much with darkness can easily get you burned :) Hermetic philosophy supposedly has its origins in Ancient Egypt (which was known as Kemet back then - which is where the word alchemy is derived from). Plato and many others were initiated into these teachings. The teachings survived over the millennium through fragments and countless translations, so what we get now might be distorted. The Kybalion has the best introduction to the subject, and once you learn it, you can recognize its principles in every phenomenon in life, and learn how to change situations to your benefit and evolution (through transmutation). Hope that helps :D