Bartimaeus Sequence

The ''Bartimaeus Sequence'' is a series of young adult novels of alternate history, fantasy and magic. It was written by British writer Jonathan Stroud and consists of a trilogy published from 2003 to 2005 and a prequel novel published in 2010. The story follows the career of a teenage magician Nathaniel (aka John Mandrake) and a five-thousand-year-old djinni Bartimaeus, whom he has summoned and nominally controls, through the alternative history of the peak of London's domination as a magical oligarchy. Provided by Wikipedia