4.5 stars. This was freaking delightful. 
 Not a perfect book, but so damn entertaining that it doesn't matter. I especially loved the worldbuilding--specifically how Cogman twisted everything around to make even the wildest ideas make sense. Justification for fae, vampire, werewolves, dragons? Check, check and check. 
 ... I want to be a Librarian. 
 And I'm very intrigued to read the rest of the series, considering something sinister is most certainly afoot. If the idea of parallel universe hopping librarians appeals to you, do yourself a favour and read this. It's incredibly charming and a whole lot of fun.