** spoiler alert ** 
 I couldn't put this book down after the first 25 pages or so. I had read Sharp Objects and Gone Girl before, so I was familiar with Gillian Flynn's style, but I still had no idea "whodunit" even by the last few pages of the book. When I discovered what happened, I was totally surprised and had to look back in the story to make sure I was getting it right. I had some twisted nightmares when I went to bad after devouring this book, but it was worth it.