Book of night by Holly Black

Charlie Hall has never found a lock she couldn’t pick, a book she couldn’t steal, or a bad decision she wouldn’t make. She’s spent half her life working for gloamists, magicians who manipulate shadows to peer into locked rooms, strangle people in their beds, or worse. Gloamists guard their secrets greedily, creating an underground economy of grimoires. And to rob their fellow magicians, they need Charlie. Now, she’s trying to distance herself from past mistakes – but going straight isn’t going to be easy.