3.5 to 4 stars. I think I would have given this 4-5 stars had I not read the Epilogue. Oh, that epilogue, which was basically a cop-out, Clare's way of appealing to both Team Will and Team Jem and it killed it for me. Which makes me really sad. 
 However, onward to my review. Clockwork Princess is the highly anticipated final book in the Infernal Devices trilogy. I loved the first two books (much more than Clare's Mortal Instruments series, which I refuse read past the 3rd book, since it was originally planned as a trilogy, and should have stayed that way, IMO). I've been Team Will from the start. You could really see the connection between Tessa and Will from the beginning. And, if not for the "curse" that Will thought was placed on him, these two would have hooked up much earlier. In this installment, however, Will realizes that his love for both Tessa and his parabatai, Jem was more significant than his own desire to have Tessa, and therefore, he (somewhat) resigns himself to the fact that Tessa and Jem will be married. It's clear that Tessa loves Jem (as she also does Will), but that love did not seem passionate - as is her love for Will. The love that Tessa displayed for Jem seemed almost familial, however, the times were such that having a marriage proposal from an admittedly wonderful man was paramount to Tessa's state in life (and the fact that she had no family left). 
 While the story focuses on Tessa and her relationships with both Jem and Will, as well as, the continuing mystery surrounding the Magister, we also get acquainted with many of the secondary characters, and their subsequent relationships. While I liked the growing sexual tension between Gideon Lightwood and Sophie, as well as the flirtatious relationship between the younger Lightwood, Gabriel, and Will's sister Cecily, it was almost too much for one book. And, this book was LONG! 
 I'm not afraid of long books, but there was just so much packed into this book, it could easily have been more than one book. In addition, there seemed to be several places where Clare could have ended the story, but it went on and on,, and on (especially with that epilogue). However, I have to hand it to Clare that she can write beautiful prose, that pull one in. Some of my favorite parts of the book were the interactions between Will and Magnus, as well as those between Will and Jem and Will and Tessa. Okay, there seems to be a theme here that all of my favorites have a common denominator..Will. Did I mention that I am Team Will? 
 One of my favorite exchanges actually occurs between Magnus and Woolsey Scott, but it is about Will, and it clearly shows Magnus's affection for Will. 
 "Are you in love with him?" Woolsey asked-all curiosity, no jealousy. Magnus wondered what it was like to have a heart like that, or rather to have no heart at all. 
 "No," Magnus said. "I have wondered that, but no. It is something else. I feel that I owe him. I have heard it said that when you save a life, you are responsible for that life. I feel I am responsible for that boy. If he never finds happiness, I will feel I have failed him. If he cannot have that girl he loves, I will feel I have failed him. If I cannot keep his parabatai by him, I will feel I have failed him." 
 "Then you will fail him," Woolsey said. 
 The inevitability of that statement was so heartbreakingly real, it made me shed a tear (or two) and not for the first, or last time while reading this book. 
 Still, Will remains hopelessly in love with Tessa, while realizing that his love for Jem is as strong - but not equal. Will speaking to Tessa: 
 "You remember what else I said to you that day in the drawing room," he said. "I want you to be happy, and him to be happy. And yet when you walk that aisle to meet him and join yourselves forever you will walk an invisible path of the shards of my heart, Tessa. I would give over my own life for either of yours. I would give over my own life for your happiness." 
 And later, when Will finds Tessa in the mountain, being held by Mortmain and he tells her (view spoiler)[that Jem has died, (hide spoiler)] the love that Will has for Tessa cannot be bottled. 
 "But he asked me to go after you..." 
 "Then you only did what he asked. You did not disappoint him." 
 "But it was also what was in my heart," Will said. "I cannot separate selfishness from selflessness now. When I dreamed of saving you, the way you would look at me - " His voice dropped off abruptly. "I am well punished for that hubris, at any rate." 
 "But I am rewarded." Tessa slipped her hand into his. She saw his chest hitch with surprised breath. "For I am not alone; I have you with me." 
 I normally love epilogues, especially at the end of a series that I have been very invested in from the start (waiting anxiously for each book to be released). In this case, however, the end of the book, for me was prior to the epilogue. The epilogue was not necessary, and made me feel angry and sad, since that is the last impression the author leaves. Ugh, if not for that epilogue. But, let me just say that all of the characters kind of get their HEA, even if this reader does not necessarily share that.