Bartimaeus is like the class clown of the djinn. Even while a slave to whichever magician summons him, he will find loopholes in the wording of direct orders. He's an irresistible character and narrates his own story with plenty of footnoted asides. When two human protagonists are facing off in a tense situation, for example, he sneaks by while disguised as a fly. In a footnote: "The fly was an optional extra right then. They were so preoccupied I don't think they'd have noticed me if I'd turned into a flatulent unicorn and pirouetted gently across the room." I'm not usually big on potty humour, but it works well here. Bartimaeus is always a delight.
I also enjoyed getting to know the guard Asmira, an admirably clever and courageous young woman who has been charged by the Queen of Sheba to retrieve a powerful ring from King Solomon. Adventure and magic and lots of fun for Grade 6 to adult.