Crowley rarely made an attempt to communicate his insights to a mass market. Magick is a terrifically complex subject to explain dry, however. The rationale behind the few fiction stories he wrote was to convey some of the arcane concepts in the midst of some semblance of a real-world context. This doesn't sound like an easy thing to do, and there is debate about how successful were the results. Perhaps this book should have been another of his plays, but perhaps he felt much more able to stoop to level of the laity with a glorious pulp fiction. He didn't do this often.
The best way to read this book might be to keep your sense of humour close by. It is Victorian, but has none of the usual stuffiness or blandness of its contempories. You should appreciate that as literary artist (and fluent French speaker), Crowley liked bold, sometimes black, brush strokes. To his mind, some natural concepts were so grand and fascinating that he would just vehemently dig in to the exploration of them. Like a maniacal anatomist of the spirit he didn't seem to mind getting his hands bright wet. On this occasion, however I think that he showed a fair amount of restraint in offending sensibilities, but if he did so on occasion in this book, it was done for noble reasons. Any talk about self-aggrandisement in this novel is completely off the mark. The vaudeville enemy in this piece is fashioned from his own DNA and with no less attention to detail than the grand white wizard and this was done self-consciously. Enjoy it!