We are now acutely aware, as if all of the sudden, that data matters enormously to how we live. How did information come to be so integral to what we can do? How did we become people who effortlessly present our lives in social media profiles and who are meticulously recorded in state surveillance dossiers and online marketing databases? What is the story behind data coming to matter so much to who we are? How We Became Our Data excavates early moments of our rapidly accelerating data-tracking technologies and their consequences for how we think of and express our selfhood today. The book explores the emergence of mass-scale record keeping systems like birth certificates and social security numbers, as well as new data techniques for categorizing personality traits, measuring intelligence, and how redlining led to the datafication of racialized subjectivity. This all culminates in an exploration of the concept of “informational persons” and the “informational power” these persons are now subject to. The recent explosion of digital technologies that are turning us into a series of algorithmic data points is shown to have a deeper and more turbulent past than we commonly think. Blending philosophy, history, political theory, and media theory in conversation with thinkers like Michel Foucault, Jürgen Habermas, and Friedrich Kittler, this book illuminates how we have come to think of our personhood in the age of information.