This a sequel to the book Little Brother. It could be read on its own but I think it is better to read the other one first and then read this one.
If you use the internet or have a smartphone then this could easily give you nightmares as you realise what sort of surveillance is theoretically possible using them. It is quite hard to get to the end of the book and not feel at least a bit paranoid.
It is one of those books set about 5 minutes in the future, so although it is sort of science fiction there is nothing in it that you can't imagine being possible now.
Despite the wealth of detail about technical matter and the culture and ethoics around them this is also a good read. If you just want techie details, buy a text book, because this has a story that makes you keep reading faster and faster because you wnat to know what is coming next.