Until fairly recently, only serial killers and lunatics had profiles. Yet today, most of us will have a profile as users of social media, and even by using the tracking capabilities on our smartphone. But where does the idea of "profiling" an individual come from, how has it changed over time and what are its implications? In this book, Andreas Bernard shows how contemporary profiling and quantification have their roots in methods developed in criminology, psychology and psychiatry at the end of the nineteenth century. Techniques for collecting data which were long used exclusively by police or to identify groups of people are now being applied to everyone who uses a smartphone or social media. GPS transmitters and measuring devices installed on bodies are no longer just instruments for tracking suspected criminals or patients, but unconsciously embraced as a way having fun, communicating, making money, or even finding a partner. Drawing perceptive parallels between modern technologies and their antecedents, Bernard demonstrates the way in which we have unwittingly internalized what were once instruments of external control and repression. This illuminating genealogy of contemporary digital culture will be of great interest to students and scholars in media and communication, as well anyone concerned about the power technologies hold over our lives.