To make an unavoidable pun Amy would love: amazing, really. Structure whore that I am, I loved the side-by-side chapters of Nick's account contrasted with "Amy's" diary, then the switcheroo in the middle. Some things I sensed coming, but most I didn't.
Though this may be categorized as a mystery, suspense, or thriller, it's my favorite thing: a novel more about the characters and their relationship(s) than anything else. Even though I've never been married, I recognized myself and others in all sorts of ways here (scary!). And even though Amy's a sociopath (I would argue, rather than a psychopath), her Cool Girl diatribe is right on; I highlighted the whole thing.So glad I didn't wait to read this any longer and before it could be spoiled for me!