I just finished it last night, and my brain is still trying to process everything. Going in, I expected a certain kind of thriller with a neat resolution, but the final chapters completely subverted that. The protagonist's big confrontation with the antagonist doesn't end with a reveal or a victory in the traditional sense; instead, it dissolves into this surreal, almost hallucinatory sequence where you're not entirely sure whose perception is real. The book just stops on this quiet, unresolved note with the main character sitting in a diner, watching the rain, and the last line is about the coffee going cold.
It's not a twist in the 'the butler did it' mold. The surprise is more in the emotional and philosophical rug-pull. You spend the whole book hunting for a concrete truth, and the ending suggests the truth was always this slippery, subjective thing that fades the moment you look directly at it. Some readers in my book club hated it, called it a cop-out. I found it brutally effective because it mirrored the book's central theme of memory decay so perfectly. It left me staring at the wall for a good ten minutes.