Alif, who prefers that online pseudonym to the name he was born with, is a young hacker with a principle of being unprincipled: he'll help anyone against the totalitarian state, without discrimination, as long as they can pay. 
 Let's start by noting that Alif is a total brat. He's incredibly annoying and sexist, and even when he tries to be self-aware and do better he STILL does it in a patronising and irritating way. However if you're able to enjoy a book while disliking the narrator (and I am), there's a lot here to enjoy. 
 Alif's problems start with a computer program he's written to identify individuals by their typing style... and which works rather better than he can explain. This kind of algorithm (without the supernatural super-accuracy) is the bread and butter of the conferences I attend, and it's not like computational linguistics gets a lot of screen time in novels (particularly not fantasy novels!) so that was a bit of a bonus for me. Then there's a magical book, and real-life djinn, and a seamless blending of Islamic folklore with contemporary life and computer hacking, which came together into a fantastical adventure. 
 The supporting characters were also fabulous. Dina, Alif's neighbour and childhood friend, is a deeply religious woman who has chosen to veil her face, in defiance of her parents' wishes, but she proves to be one of the strongest characters throughout. Similarly Vikram, a djinn they expect to be dangerous, shows himself to be a valuable ally.