I LOVED THIS BOOK! 
 Fantastic plot, amazing research and information, well written, lovely characters! I just about fell in love with Will and Jem, and Tessa was one of the female characters that I will continue to marvel at, because of her strong personality and dedication! 
 I loved the way Clare wrote out the story, introducing new ideas and characters (and their origins a.k.a Downworlder, Mundane, etc...) and how she would include little notes of information about new things before moving on with the story. That ensured that the reader won't get lost as to what exactly this new character entails..