There’s no doubt in my mind that the title of this post is true. Sure, the Harry Potter books get more angst-ridden as the kids get older, and sure, the stakes get higher when Voldemort is trying to take over the world and generally deploy his Evil Schemes. But you can keep your graveyard incantations and Departments of Mysteries, your snakes and corpses and lakes full of zombies. Harry Potter is never as scary before Prisoner of Azkaban, and it never gets quite that scary again.
Because the scare quotient (if I can use that phrase) of Prisoner of Azkaban doesn’t depend on gross images or Gothic idioms, it doesn’t depend on dark magic or evil ideologies. The story does more than just startle or alarm us. It unsettles. It gnaws away at us with a, creeping, oozing fear that pricks under your fingernails and round your eye sockets. And it’s the only book with scary not just as decoration or set design; the fear is embedded in the story itself.