The scale and patterns of urbanization today challenge the notion of permanence as the default condition for cities and the urban environment. At the same time, rubrics like informality have become counter-productive, as they implicitly aspire to create new processes in imagining permanence. But, does permanence, as the sole instrument of urban vision, really matter? For the over 700 million people represented in the research behind this book, stability is a luxury, if not superfluous. Permanence is not affordable and does not really affect their daily existence. So, what does this mean for the discipline of architecture and urban design? In light of this and other associated questions, this book offers an unusual atlas of those practices that create urbanity without concern for permanence.