This is a nice book, whose value is more in its message that in the story itself. 
 The message is that everybody has right to be different and that we should cherish diversity instead of laugh at it or isolate it. 
 The story is that of a 7 years old girl who is bullied because different and whose only friend is her Granny, who introduces her to a fairly tale world that helps young Elsa both to escape and to understand the reality she lives in. Unfortunately Granny dies, leaving Elsa alone and in charge of a treasure hunt that will change the life of all the adults living in her building. 
 So Elsa joins the large group of precocious and totally unbelievable children that writers love to put into books for the sake of cuteness and comedy. Don't get me wrong, Elsa is a perfectly likeable character and you start to feel for her since the first pages; her loneliness, her combination of cleverness and naivety (and her love for Harry Potter) really strike a cord in the reader and I found myself following her treasure hunt with trepidation and pathos but her character felt too much of a cliche to be totally comfortable with it. The same can be said of her fabulous Granny who was too much of a superhero to be completely believable and, while the author presented her as a free thinker, sometimes she was simply and unduly petty. 
 Backman voluntarily blur the lines between reality and the fantasy world of Miamas, using fairy tales to tell the adventurous lives of the different characters, a nice idea a bit spoiled by the lack of real charm of this fantasy world, that has too many similarities with other famous children stories for my taste. 
 The entire book is a fairy tale in itself because you have to suspend a bit your rationality to accept that a young girl can come home from school with new bruises without her loving mother ever doing anything about it or that Elsa is left always without adult supervision when every adult in her life know that a potential killer is following her. 
 In the end I appreciated the intent of the book and I found it really moving when it described parent-children relationships but I also felt that it lacked in originality to be really considered a "good" book.