The Amulet of Samarkand - Jonathan Stroud

This first installment of the Bartimaeus Trilogy has two protagonists. There's Nathaniel (shh, that's his birth name! And names have power!), later called John Mandrake (his official magician's name), an eleven-year-old magician's apprentice. He's apprenticed to a weak, abusive magician who takes out his frustration about his stagnant political career on Nat. In this world (set in contemporary time), magic is real and magicians are the (educated) ruling class; they control the British government, and by extension the rest of the Empire. Whose entire power comes from their mastery of demons, from the weak imps and foliots to the common djinns to the powerful afrits to the so-powerful-at-least-two-magicians-are-needed-to-summon-and-control madrits, to even more powerful (but fortunately uncommon) beings.
Speaking of the supernatural, our second protagonist is Bartimaeus. He's a medium-power djinn who shapeshifts a lot, and has a quick wit, plenty of sass, snark and sarcasm, an over 5000-year-long backstory (barely hinted at in this book), and an oversized ego. The chapters told from his (first-person) perspective are also a much more fun read than those from Nathaniel's (third person narration), not only because of Bartimaeus' wit but also because of his liberal use of footnotes. This makes sense if you've read the book.
I particularly liked how the vocabulary and themes were beyond what is expected of a YA novel: Bartimaeus is a very articulate djinn indeed, and this novel doesn't shy from tackling prejudice, social injustice, oppression, and other interesting stuff. It's a really good novel! Read it now!