"Gather, Darkness!" by Fritz Leiber (1943)
"But the Black Man had gained time to act. His own wrath ray lashed out, swished into that of Cousin Deth's. Since the two rays were mutually impenetrable, unable to cut through each other, Deth's was fended off...."
"Gather, Darkness!" was serialized in 1943, and it appeared in novel form sometime thereafter.
The story takes place in the distant future, though the Earth of this future resembles medieval Europe. A priesthood, with all the weight of an advanced technology at their disposal, seek to maintain dominion over an ignorant population of farmers, artisans, and tradespeople.
And while it might sound like a great idea, this book has a lot of flaws. The most fundamental of these flaws is the book's general premise - that a group possessing advanced technologies would want to pose as a theocracy, ordained by a "Great God" that they themselves don't believe in. I find such a proposition hard to swallow, especially in the absence of a first cause which might explain why they chose this strategy. Would they really enjoy their dominion over the ignorant? Wouldn't they find this dominion as confining as the serfdom of the peoples they rule - if not more so?
It is moreover unlikely that the rank and file priesthood would be aware of the deception. A workable conspiracy would require their ignorance even more than their complicity. Otherwise, the nature of their undertaking would be obvious to all. This is how pyramid schemes work - only those at the top of the pyramid are truly aware of how the scam functions. Those at the bottom of the pyramid must be invested enough to commit to the scheme. If they aren't, the scheme becomes obvious to all.
Beyond the general premise, there is also the problem of the protagonist's change of heart. In the first chapter he proclaims the falsehood of his occupation to the commoners, he reveals the priesthood's technological tricks, and he despises religion itself as a tool of the ruling class. Yet halfway through the book he somehow changes his mind, and the author never bothers to explain why. For some inexplicable reason he joins the rebels, a group who would be - to his thinking - just as corrupted by religion as the priesthood he has left behind.
Thirdly, there are grammatical issues in this book which seem to go beyond sloppy editing. I'm still puzzling over words like "unwieldily," and "horrifiedly," which seem, given the sentences in which they are present, to have been part of the original manuscript. The author often seems less than certain of his grammar, and while I would readily dismiss this flaw in other science fiction novels, in "Gather, Darkness!" it seems more systemic, more pervasive, and more traceable to the person who wrote the book. It seems, in other words, a symptom of lazy thinking.
It is very possible that Fritz Leiber wrote better books. I certainly hope so. As it is, "Gather, Darkness!" has lessened my enthusiasm for this author.