Is gentrification necessary for urban renewal? To what extent is it a natural course of events, and to what extent is it being induced? The process of transforming a low-income neighborhood into a middle-class enclave, often driven by members of the creative classes, used to start from the bottom, as seen in run-down parts of London and New York. It has since been discovered by the market, and developers now look to lure creative industries and cultural facilities as top-down mechanisms to kick-start the process. This issue of the architectural journal OASE explores the theoretical background of the gentrification phenomenon from perspectives including the visual arts, cultural history, economics, landscape and urban design and sociology. It also includes case studies on London, Amsterdam, Rotterdam, Antwerp and Vienna.