** spoiler alert ** 
 Wow. I almost literally cried through this entire book. Everything I love about Cassie Clare's writing was on point -- the action, the character's conversation, the character's self-discovery. I enjoyed meeting Cecily and I also enjoyed hers and the new romances that came out of this book. (Woo for Gideon and Sophie!!) 
 I have always been Team Jem, so this is why I cried my way through the book. The reason this gets 4 stars instead of 5 from me is that while I love how they ended the story for Will and the other characters, I did not really understand the choice to make Jem a Silent Brother. It feels to me that Cassie Clare just did it because a fan suggested it, and that way he can come around in the end and Tessa can have both of them. But it makes no sense to me. 
 Jem seemed content to die. He told everyone to stop looking for the cure and that he didn't want to fight to live (though he would for them.) Then why, at the last minute, is he like, "Wait, J/K, I wanna be immortal, basically." And after it happens he doesn't seem happy about it. He's all (and I'm paraphrasing), "Silent Brothers can't play music and lead a lonely life." Then, at the end, it's like he was looking for way out of being a Silent Brother and finally got it? (By the way, does this relate to something that happened in the Mortal Instruments books? Because I don't remember.) 
 So, yeah. I'm Team Jem and I think the book would have been even more powerful and amazing if Jem had simply died.