The second book in the Bartimaeus trilogy was amazing. It plays with your emotions and character allegiances a lot, and I felt incredibly conflicted most of the time over who I wanted to succeed. In the previous book, Nathaniel was at risk of being swallowed by the Magician's culture of power, greed, and betrayal. Now in this book, he's fallen into it head-long. Only a few sparks of his conscience can be seen anymore, but as he's the main character, the reader still feels allegiance to him. This is partially because we know Nathaniel has the potential to be honourable and good and we desperately hope he'll be able to live up to that potential. One of the antagonists, Kitty Jones is a member of the resistance that Nathaniel is trying to destroy. Some of the chapters are told from her point of view and she is much better morally than Nathaniel. Her sad backstory also moves the heart of the reader in her direction, leaving the reader unsure who to side with. If Nathaniel doesn't stop the resistance, he'll be in big trouble, but if the resistance is stopped, Kitty will be in trouble.
Few books have ever been able to create such a feeling of conflict and suspense in me before. The book was one of the best I've ever read!