This book was BRILLIANT! it was snarky but not overly sarcastic. O'Malley set up a structure in this book that enables the reader to get engrossed while still getting good bouts of solid info. I realize I just made it sound terribly boring but it's not, it's really quite brilliant. ok enough slobbering over O'Malley's book structure. 
 The main character is very interesting...well both of her personalities are. The world O'Malley creates in the Chequy Files is a fascinating blend between shadowhunters, the Bourne identity, Miss Peregrine's Home for Peculiar Children and a fantastic mystery. The characters are interesting, the description is very well done, and the story drives the imagination. The only reason this book didn't get a raving 5 stars is because of the increase in language towards the end.