Informalize! is the first book in the forthcoming Essays on the Political Economy of Urban Form series developed at WERK 11, a research hub of the ETH Zurich bringing together the various fields that have an impact on today's urban conditions. Edited by Marc Angélil and Rainer Hehl, this collection of four essays presents a cross-section of urban informality drawing on broader theoretical frameworks as well as case studies from Casablanca, Belgrade, and the Global South. Reading the city of yesterday as the physical manifestation of the failure of the urban economy to meet the needs of a growing population, Informalize! turns to the city of today and tomorrow as the representation of a paradigmatic shift toward new social, political, and economic orders and ways of collecting and applying urban knowledge.