Synopsis:

First of all the cover of the book is not the puke-green you see here.

Back of book;

Nathaniel is eleven years old and is a magician's apprentice, learning the traditional arts of magic. All is well until he has a life-changing encounter with Simon Lovelace, a magician of unrivaled ruthlessness and ambition. When Lovelace brutally humiliates Nathaniel in public, Nathaniel decides to speed up his education, teaching himself spells way beyond his years. With revenge on his mind, he masters one of the toughest spells of all and summons Bartimaeus, a five-thousand-year-old djinni, to assist him. But summoning Bartimaeus and controlling him are to different things entirely, and when Nathaniel sends the djinni out to steal Lovelace's greatest treasure, he finds himself caught up in a whirlwind of magical espionage, murder, and rebellion.

There is one major problem with this description.

The books are called The Bartimaeus Trilogy for a reason. The back of the book makes it sound like main character is Nathaniel, when really it's Bartimeaus.