City of Glass is the third and final book in the Mortal Instruments series, and far surpasses the first two in terms of quality and plotting. The first 100 or so pages seemed to drag a bit, mainly focusing on the logistics of getting all the main characters to the places they needed to be. Once past that, the story kicked into high gear, and didn't slow down again until the epilogue. City of Glass successfully pulls together all the various threads started in the earlier books. Clary and Jace have plenty of tortured, forbidden moments and anguished soul-searching. The fate of all Shadowhunters hangs in the balance, and it is no small thing to acknowledge that the author pulls off a satisfying climax, full of drama, tension, and tragic moments, while incorporating all major and minor characters into the action. I heartily recommend City of Glass, and would definitely say that the Mortal Instruments series is worth your time.