Klein's one-and-only novel is not just a great horror novel -- it's a great novel in any genre. What he pulls off here is extraordinarily rare, creating a text that manages to work what can be seen as metafictional commentary on, in this case, the entire history of horror fiction into a structurally elegant and compelling horror novel populated with flawed but sympathetic characters.
Stripped to its basics, The Ceremonies tells the story of a 30ish New York City grad student in English literature whose thesis is on Gothic and horror literature, and whose life suddenly starts to resemble some of the works he's reading over the course of a summer.
Klein comes up with one of the most innovative reworkings of the "forbidden book" trope in horror fiction that I can think of. Normally, the forbidden book (say, H.P. Lovecraft's Necronomicon) is a text invented for a work of fiction which, within the world of that fiction, reveals in whole or in part the secret workings of the universe. Generally, a forbidden text is rare, dangerous even to read, and filled with knowledge that undermines all cultural norms when it comes to religion. For example, the Necronomicon reveals that all human religion is a comforting lie that obscures the true, horrifying and precarious state of humanity in a universe that is consciously hostile towards us.
But as the malign Old One muses in the novel, forbidden knowledge never stays hidden. As a character in another Klein story notes, if the Necronomicon really existed, it would be available in paperback in any book store. What Klein posits here is that the real forbidden knowledge of the world (which includes the malevolent and world-threatening ceremonies of the title) is, like Poe's purloined letter, hidden in plain sight: an off-kilter tarot deck here, a strange Eastern European folk dance there, and, most significantly, the real Victorian-era horror writer Arthur Machen's sinister tale "The White People" right in the middle of it all. And what the Old One -- a deceptively jolly looking old man turned into a psychopathic apostle of an invader from Outside back when he was a boy in the 1870's -- can do is reassemble the ceremonies from a variety of sources and, when the stars are right, usher in what will be a really, really, really, really bad New World Order, at least for human beings and, in fact, every living thing on the planet.
There are a lot of delights both light and dark in the novel -- Klein's always fascinating evocation of New York; the grad student's often hilariously apt musings on the strengths and deficiencies of various classic Gothic and horror texts (he finds Henry James a big fat bore and "The Turn of the Screw" the most over-rated ghost story in history, an observation I wholeheartedly agree with); the odd rural reality of the Brethren, a vaguely Amish religious group whose settlement in New Jersey is the backdrop for much of the novel; and the horrifying inner life of the Old One, possibly the least romanticized hyper-intelligent serial killer in the history of horror fiction. The novel fairly hums along, dense enough to reward second and third readings but compelling enough to work almost entirely on the level of ever-tightening suspense.
Terrible things happen to good characters here, all of it justified by the text, and while the storyline is dead serious, Klein manages to slip in enough parodies and inversions of classic tropes to keep one intellectually occupied (the novel's gender-inversion of the traditional Lovecraftian Vagina Dentata Invader from Outside is a real pip; so, too, is what happens to the one good character who knows exactly what's going on and has been charged by Something with the task of halting the ceremonies).
In any case, highest recommendation. Existential terror at its most entertaining.