Mattern’s A City Is Not a Computer dismantles the dominant metaphor of the city as an information-processing machine and replaces it with a plural theory of urban intelligence. Its iconic idea is that cities think through libraries, trees, maintenance workers, communities, infrastructures, histories, documents, interfaces and material practices, not only through dashboards, sensors and optimisation systems. The theoretical contribution lies in refusing computational reduction without rejecting computation itself: urban intelligence becomes distributed, embodied, institutional, ecological and archival. Methodologically, the book operates through media archaeology, design criticism, infrastructural analysis and civic epistemology, reading urban technologies against longer histories of public knowledge. Its conceptual operation is de-computation: the city is released from the narrow ontology of the machine and restored as a layered medium of collective knowing. The bridge to the wider field connects urban studies, STS, media theory, library studies and design criticism, showing that smartness is a political arrangement of epistemic infrastructures.