C. S. Lewis wrote a book Surprised By Joy. It's about his conversion to Christianity. Desire for Joy is what he experienced as the deepest Desire. He couldn't find this Joy in worldly and sexual pleasures and in the occult (what he poetically named the World, Flesh and the Devil).
I haven't read the whole book. It caught my attention because of some passages dealing with the occult. It's the only book that talks about "spiritual lust". Here's one passage that may be of interest to you:
Two things hitherto widely separated in my mind rushed together: the imaginative longing for Joy, or rather the longing which was Joy, and the ravenous, quasi-prurient desire for the Occult, the Preternatural as such. And with these there came (less welcome) some stirring of unease, some of the immemorial fear we have all known in the nursery, and (if we are honest) long after the nursery age. There is a kind of gravitation in the mind whereby good rushes to good and evil to evil. This mingled repulsion and desire drew towards them everything else in me that was bad. The idea that if there were Occult knowledge it was known to very few and scorned by the many became an added attraction; "we few", you will remember, was an evocative expression for me. That the means should be Magic--the most exquisitely unorthodox thing in the world, unorthodox both by Christian and by Rationalist standards--of course appealed to the rebel in me. I was already acquainted with the more depraved side of Romanticism; had read Anactoria, and Wilde, and pored upon Beardsley, not hitherto attracted, but making no moral judgement. Now I thought I began to see the point of it. In a word, you have already had in this story the World and the Flesh; now came the Devil. If there had been in the neighbourhood some elder person who dabbled in dirt of the Magical kind (such have a good nose for potential disciples) I might now be a Satanist or a maniac.
In actual fact I was wonderfully protected, and this spiritual debauch had in the end one rather good result. I was protected, first, by ignorance and incapacity. Whether Magic were possible or not, I at any rate had no teacher to start me on the path. I was protected also by cowardice; the reawakened terrors of childhood might add a spice to my greed and curiosity as long as it was daylight. Alone, and in darkness, I used my best endeavours to become a strict Materialist again; not always with success. A "Perhaps" is quite enough for the nerves to work upon. But my best protection was the known nature of Joy. This ravenous desire to break the bounds, to tear the curtain, to be in the secret, revealed itself, more and more clearly the longer I indulged it, to be quite different from the longing that is Joy. Its coarse strength betrayed it. Slowly, and with many relapses, I came to see that the magical conclusion was just as irrelevant to Joy as the erotic conclusion had been. Once again one had changed scents. If circles and pentangles and the Tetragrammaton had been tried and had in fact raised, or seemed to raise, a spirit, that might have been--if a man's nerves could stand it--extremely interesting; but the real Desirable would have evaded one, the real Desire would have been left saying, "What is this to me?"
