Megaprojects are not merely transformative, but rather inherently disruptive. They are incompatible with any approach to urban sustainability that prioritizes the well-being of urbanites and the boundaries of the Earth system. In fact, megaprojects undermine efforts to tackle the global impacts associated with both the destructive creation of capitalism and the new climate regime. The reason for this state of affairs is not cost overruns and poor megaproject management, but the disruptive impacts that megaprojects have on urban areas. This book emphasizes the megaproject impacts imperative: the importance of identifying impacts as a prerequisite for critically assessing whether megaprojects should be built. Drawing on 18 megaprojects in 16 cities around the world (inter alia, Istanbul, Hong Kong, Abu Dhabi, Barcelona, Boston, New York and Shanghai), Contesting Megaprojects illustrates urban-regional trajectories over the past fifty years. These trajectories show the coexistence of property development, culture, and iconic architecture, together with a more recent interest in science and technology, innovation, and sustainability as strategies to foster urban competitiveness. Megaprojects cause massive disruptions everywhere, and the book offers a typology of megaproject impacts: socioeconomic, environmental, spatial, political and geopolitical, financial, cultural and systemic. As a response to this emerging complex web of interrelated megaproject impacts (disruptive complexity), the book develops the concept of complex sustainability, a transdisciplinary approach to urban sustainability, through socioeconomic sustainability and deep sustainability. The critical outlook of this book elicits fundamental debates around capitalist development: trickle-down urbanism, spectacularization, high-tech innovation and AI, planetary boundaries, global risks, resilience, the right to the city, geopolitics, democracy, prosperity, and power. Contesting Megaprojects can help urban scholars and analysts, practitioners, policymakers, and residents of cities better understand the complex impacts of urban megaprojects, their magnitude and consequences, and identify courses of analysis and action toward a more sustainable and just future.