4 is really rounding up from 3.5. This is a very pretty, whimsical, romantic book, and I thoroughly enjoyed being along for the carousel ride. It's also structured in a way that made it easy to breeze through: the chapters are very short, not unlike the little photograph-inspired vignettes Morgenstern posts regularly on her website, and they are intricately arranged to spiral down to the moment of crisis. Now, intricacy should not be mistaken for complexity or depth, but that's not what you want this book to do. You want this book to take you into a circus tent and show you something wonderful and fleeting, so that's what it does.