Parents' Guide to City of Glass: The Mortal Instruments, Book 3

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Common Sense Media Review

By Matt Berman , based on child development research. How do we rate?

age 14+

Exciting, violent series cycle concludes with a bang.

Parents Need to Know

Why Age 14+?

Any Positive Content?

Parent and Kid Reviews

age 15+

Based on 8 parent reviews

age 12+

Based on 45 kid reviews

Kids say the third installment of the series is an action-packed and intense read that features significant violence, some language, and themes suitable for mature readers, generally aged 11 and above. Many reviewers highlight the strong character development, gripping plot twists, and the blend of romance and fantasy elements, making it compelling for fans of the genre.

  • exciting plot
  • character development
  • mature themes
  • intense violence
  • fantasy elements
Summarized with AI

What's the Story?

In this conclusion to the Mortal Instruments trilogy (the conclusion to the first cycle of three anyway), Clary makes her way to the hidden Shadowhunter country of Idris, seeking a cure to her mother's magical affliction. While there, her father delivers an ultimatum to the Shadowhunter ruling council: declare him their leader, or he will use the Mortal Instruments to unleash a plague of demons and wipe them out. Meanwhile, Clary struggles to learn how to use her unique powers, discover her secret heritage, and figure out her relationship with her maybe-brother, Jace.

Is It Any Good?

Our review:
Parents say ( 8 ):
Kids say ( 45 ):

Derivative, predictable, and melodramatic can be good things when they're played for fun and done well, and this is done really well. Action, horror, complexity, romance, twists that aren't too hard to see coming, mysteries the reader will figure out before the characters -- they're all here, in just the right amounts, and mostly with just the right pacing, though, like most 500+ page books, it sags in places.

It's easy to find things to criticize: the climactic battle happens offstage; the religious and incestuous aspects may disturb some; there's a fair bit of repetition. But with characters who grow ever more satisfying, a cleverly detailed fantasy world, a thoroughly engrossing writing style, and a host of questions from the earlier books answered before the end, fans of the series will find this everything they had hoped for. And if you haven't read the first two books? Don't even think of trying this.


Talk to Your Kids About ...

  • Families can talk about the classic creatures used here. Why are vampires and werewolves always popular? How are they different here from the Twilight series?

  • Families can also talk about the violence in this book, and the whole series. Books 2 and 3 are especially bloody. Do you think the fantasy element makes the gore easier to handle?

  • The series seems to neatly end here, yet the author released a fourth book (part of a second cycle of three) and a prequel series -- starting with Clockwork Angel -- besides. There's also talk of a movie deal. Do you think more is better, or would you rather the series ended here?

Book Details

  • Author : Cassandra Clare
  • Genre : Fantasy
  • Book type : Fiction
  • Publisher : Margaret K. McElderry
  • Publication date : March 1, 2009
  • Publisher's recommended age(s) : 14 - 17
  • Number of pages : 541
  • Last updated : October 9, 2025

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