Urban correction begins when the city’s official descriptions are no longer trusted as sufficient. Displacement, gentrification, misrecognition, datafication and infrastructure often produce realities that standard planning language cannot adequately register. KnowledgeFriction names the productive resistance that appears when evidence, lived damage, institutional categories and public truth do not align. It is not confusion. It is the necessary friction through which better urban knowledge becomes possible. This reader begins with displacement beyond removal. Knieriem, Lagendijk and van Leeuwen’s work on Rotterdam’s Tweebosbuurt shows that gentrification is not only the physical relocation of residents. It is also misrecognition: humiliation, civic erasure, disregard, denial of standing and the destruction of social dignity. Residents do not only lose space. They are told, directly or indirectly, that their attachments, histories and claims matter less than redevelopment narratives.

Schnelzer’s processual theory deepens this by distinguishing becoming displaceable, feeling displacing and un/doing displacement. Displacement is not a single event. It is a distributed condition that begins before eviction and continues after relocation. It includes vulnerability, anticipation, fear, manoeuvre, adaptation and the gradual reorganisation of everyday life. Elliott-Cooper, Hubbard and Lees call this un-homing: the destruction of home’s conditions before, during and beyond physical movement. Slater’s return to Marcuse insists that displacement must remain central to gentrification theory, not treated as an incidental or difficult-to-measure side effect. KnowledgeFriction emerges because these experiences often exceed available data. A rent increase can be measured. A demolition notice can be archived. But humiliation, anticipatory anxiety, loss of neighbours, symbolic erasure and civic disrespect are harder to count. This does not make them less real. It means urban knowledge must expand its evidentiary forms. DiagonalReading becomes a secondary operator because the problem must be read across categories: housing, affect, law, infrastructure, race, class, data, cartography, public language and bodily exposure.