I thought Ariel would post on this first because she mentioned reading it on her family blog. Guess I beat her to it. This is another hit for Cassandra Clare in my opinion. I really enjoyed this book. I again enjoyed the originality of her storyline. And this time, there is no mention or possibility of incest. HALLELUJAH!!!
So with this series, (and many of us have already posted on the Mortal Instruments trilogy and how much we've enjoyed them,) the Mortal Instruments books are like the Star Wars movies I grew up with - A New Hope, The Empire Strikes Back, Return of the Jedi. They are actually books 4, 5 and 6 of the Star Wars series. So this book is like Star Wars One: The Phantom Menace, though very fortunately, there is NO JAR JAR BINKS to be found in this story.
There's even a cameo by a familiar character from the Mortal Instruments books.
You don't have to read the first three, well I guess #4, 5 & 6 - and though there can be a worry that 1-3 won't be as good as 4-6... don't worry. I really enjoyed #1.