Books like Ptolemy's Gate by Jonathan Stroud

Three years after thwarting a cataclysmic attack on London, Nathaniel has become a prominent member of the British Government, but rising foreign wars, enemy incursions, and commoner unrest test his resolve. Amidst growing tensions, his relationship with Bartimaeus deteriorates as the djinni’s power wanes from extended time in the mortal world. Meanwhile, Kitty, ever a rival, secretly researches magic, demons, and Bartimaeus’s past, devising a daring plan that could break the endless cycle of conflict between djinn and humans. In this climax of the Barton series, Nathaniel, Kitty, and Bartimaeus face treacherous magicians, a complex conspiracy, and a rebel faction of demons. Their survival hinges on pushing the boundaries of their world and confronting their deepest selves, ultimately forcing them to learn to trust each other.

First publish date: 2005