**Note: if you're looking for a useful review that will provide cogent analysis of the book, please look elsewhere. This is my random, 10-minute, offhand reaction. I'm going to talk about themes. Depending on your definition, you may consider it spoilery. You've been warned.**
In some ways, speculative fiction often balances precariously on the boundary between detective fiction and horror. Some books--hard scifi is a prime example--seek to make a world that they can explain. No matter how bewildering everything seems to be, somewhere, somehow, you just know it all makes sense. And then there's the horror flavour. At its core, horror comes from the unknown. So horror must play upon the unguessable, the nonsensical, the inexplicable.
Area X falls firmly into the latter category. It's the purest novelistic form of the Weird scifi subgenre that I've ever encountered. And from the very beginning, it's clear that the story itself will be a quest--a failed quest--to make the world make sense. The titles reflect the nature of the story arc. In the first part, Annhilation, the protagonists discover the effects of Area X upon their once-stable, sensible world. In the second,Authority, they try to take control and, as can be predicted by the outset, utterly fail to do so. In the third, Acceptance, the protagonists finally come to terms with the fact that Area X simply cannot be understood.
I'm a reader of detective fiction. I like order. I don't need to hear the explanations, but I need to know that somewhere, they're out there. The whole point of Area X, as is clear from the very beginning, is that it cannot be explained, and it doesn't make sense. This book, therefore, was something of a mismatch for me.
Even so, Area X is a fascinating book. It's practically constructed whole-cloth from metaphor and allusion. All of the names are meaningful, from the identity-stripping designation of "Biologist" and "Psychologist" to the man who designates himself as "Control" at the times when he has absolutely none to Saul the lighthousekeeper who is blinded by light. It is a thoughtful, complex book, and it will leave you still wondering about it long after you've finished.
Granted, if you're a detective-type reader, your primary question will probably be "What the hell?", but the book is multilayered enough to leave questions for everyone.