I read this one a few weeks ago, but wanted to wait until I saw the movie before diving into my thoughts. Both start extremely similar, down to some exact word-for-word scenes, and the plot points are all the same, but the movie takes some creative license to show what’s going on for the main characters mentally that the book doesn't. This works in favor for both the book and movie. In the book's case you're left guessing, confused, and trying to pick apart every tiny detail til the very end. The author is continuously sneaking small details/hints past you without raising alarm, and at the end I found myself looking back to see a whole different story. This isn't to say I didn't see the twist coming, but it was done in a way that left plenty of good stuff to pick apart after you‘ve finished.