Transparency is a quality that renders an actor, object, or social relation knowable, revealing the process by which it comes into being without affecting its character. For anthropologists, the idea of transparency is in constant tension with obscurity and secrecy. Across the corporate, governmental, and nongovernmental contexts where it is promoted, transparency unleashes unexpected social effects, often occluding more than it discloses. Transparency is not neutral; it can create new power relations and transform the social situations it claims to merely reveal. This unexpected potential has turned anthropology's attention toward the quantitative, narrative, and documentary instruments used to promote transparency. Knowledge of these instruments and the capacity to interpret them orders new hierarchies of subject positions and transforms the politics of collective life.