Whether or not you will allow this book into your home will almost certainly boil down to one main question. Specifically, should your child be allowed to read a book that contains main characters who are ghosts. And this book represents the most interesting version of that question, as it is an overall wonderful story with no feeling of anything dark throughout… and the ghosts are “good” characters… and yet, the fact remains, that they are still ghosts. — The event that leads to the characters referenced above becoming ghosts is a fire that occurs before the start of the book. This is referenced throughout and it is clear that they passed away because of the fire. While the author is careful to keep this from coming across in a frightening way, the idea of a deadly fire in a library may still bring worry to certain children. — There are a few sparse shots at overprotective parents. In one place a comment is made that a friend’s parents are worried he may “catch a cellphone addiction”. This is unfortunate in a world that certainly pushes hard towards not protecting children’s hearts and minds nearly enough. — A father character is shown to be mostly absent and this is never really clearly shown as wrong (Mom isn’t shown much, but when she is she is described as being on the phone working a lot). — The final potentially concerning item is an interesting one. This book does a wonderful job of highlighting people who have a love of reading. The only potential concern is that it doesn’t shed light on the case where this goes too far and people fall into the trap of escaping life within the pages of a never-ending series of books. Anything in this world, if taken too far, becomes sin.