Surveillance permeates every aspect of our lives today. Every click on the keyboard, every call, text or email, every purchase, every contact with a doctor or the police or a government department, each time you walk under a video camera or pass through a security check, and in many other ways, you are recorded, identified, traced, and tracked. Who processes this free-flowing data, how, and with what consequences, is a critical question affecting everyone.

Surveillance is not inherently good or bad but neither is it neutral. It urgently needs to be understood better because people's lives and life-chances depend on it. Today surveillance is central to doing business, meeting friends, organizing governance, maintaining security, and being entertained. Surveillance requires not just exploration and understanding but ethical guidance and political debate. How you get credit or welfare benefits or get on a no-fly list or are ranked as a consumer depends on surveillance. This Very Short Introduction investigates how surveillance makes people visible, how it grew to its present size and prevalence, how it came to rely on technologies of data-handling, and how it developed its own cultural features. Throughout, David Lyon also considers the ethics of surveillance, and explores its potential in prompting political struggles.