Dion Fortune wrote what is often considered to be one of the best introductions to Hermetic Qabalah, 'The Mystical Qabalah'. Excellent though it is, it presents only half the picture - something Fortune herself was keen to point out. The key to understanding that book is found instead in her fiction writing. 'The Sea Priestess' is one such novel. It presents the keys to understanding the 9th Sephirah of the Qabalah, Yesod.
The book is often sited as an influence on modern paganism and especially, modern Witchcraft - and you can see why. The lead character of Morgan Le Faye makes for an alluring role model. However, hermetic and alchemical teachings are very often presented as stories or symbols because they are meant to set your mind in motion - they aren't meant to be taken literally, as concrete reality. The real lessons in this book are alluded to through the relationship between Wilfred and Morgan, but it's the later relationship between Wilfred and Molly that really delivers the goods.
So we have two levels to this book. 1. It's a good, easy to read piece of new age fiction. Yes, the language is a bit dated now (it was written in the 1930's after all) but none the less entertaining for it, and the story jogs along at a good pace. All told, not a bad read. 2. It's a cleverly presented initiation into the mysteries of one of the spheres of the Qabalah, and in a world of 'pop' magic and spirituality type books, fake guru's and 'positive thinking', that makes it invaluable to me. Just don't forget to get hold of 'The Mystical Qabalah' as well. And remember, you're not so much reading a book as receiving a lesson from the Inner Planes - if you can read between the lines.....