This article examines a recent, unexamined turn in the history of personal data in the last half century: the era when it was re-envisioned as a possession of the individual whom it described or from whom it was obtained. Data-whether scientific, commercial, or bureaucratic-had often been treated as confidential or protected, but it had not typically been conceived in terms of individual ownership. But starting in the later 1960s, more and more people in the industrialized West questioned whether they or the authorities who collected or maintained their data properly had claim to that information. This question was sparked as much by political and economic developments as it was by scientific and technological ones. Citizens' move to shore up their proprietary claims would prompt new regulations around access, control, and consent that continue to undergird contemporary ideas about personal data. A product of social movements and civil rights reforms as well as market thinking, this bid for authority over one's "own" information would however reveal its limitations by the turn of the twenty-first century, particularly in the context of a big data economy. This essay is part of a special issue entitled Histories of Data and the Database edited by Soraya de Chadarevian and Theodore M. Porter.
