The Book of the New Sun by Gene Wolfe. Despite there being hundreds of writings out there dedicated to figuring out this work, I have yet to see anyone mention the fact that it is, quite obviously, a book that has been deeply influenced by occultism and is all about the occult. It’s clear from start to finish. A major character is even called “The Black Sun”! And for good reason.
No one in the book is sitting around doing evocations as we would understand them. Maybe, perhaps, it is one long evocation. The magick that occurs is subtle, hidden from view, disguised, yet it pervades the entire work and becomes more obvious as you continue reading through the entire two volumes. For fear of revealing too much, it represents a view of reality and the way it works that is consistent with our own, but hides it under high strangeness and extreme technology, but that technology is infused with occultism and the power of belief/thoughts/feelings to warp reality in ways far more bizarre than any of the technology described in the book. At best, the technology presented in the book is in fact technology that has been designed around the subjective/malleable nature of reality.