Conventionally understood as the operative substrate of contemporary global life, the term »infrastructure« invokes systems such as physical networks for transportation and communication, the organization of waste and utilities, resource flows, digital management, and capital movements. Moving away from these material associations, freethought develops the notion of »spectral infrastructure« toward the ghostly, affective, and fugitive intensities that undergird both infrastructural and quotidian life. The research conjures the invisible, inaudible, and illegible through textures, rhythms, atmospheres, invocations, gestures, vernaculars, and affects—elements that escape traditional forms of tracking or measurement, calling instead for experimental forms of mapping, sensing, and tracing. freethought is a collective working in public research and in curating concepts of urgency. Irit Rogoff, Stefano Harney, Adrian Heathfield, Massimiliano Mollona, Louis Moreno, and Nora Sternfeld formed freethought in 2011. Traversing disciplines, blending influences, and borrowing forms, freethought experiments with new combinations of criticism and practice in the arts. »Spectral Infrastucture« is a Public Editorial Meeting convened by freethought and BAK, basis voor actuele kunst, Utrecht in collaboration with art education, HFBK Hamburg.