This book explores how urban sustainability is negotiated and enacted through planning practices, narratives, and institutional change. It does so through the case of Aalborg, to illustrate transitions that are shaped by urgency, legitimation and implementation. It offers a theoretically grounded and empirically nuanced account of how urban sustainability emerges through situated, negotiated, and contested processes of transition. The book provides critical insight into the governance arrangements, planning rationalities, and institutional innovations that shape sustainability in practice, with the city of Aalborg serving as a paradigmatic case. Drawing on four intersecting theoretical traditions – Urban Political Ecology, Just Sustainability, Phronetic Planning, and Urban Sustainability Governance – the book develops the Urban Sustainability Compass, an interpretive framework organised around the logics of urgency, legitimation, and implementation. Through longitudinal analysis, engagement with planning documents, and sustained collaboration with municipal practitioners, the book delivers conceptual depth and methodological guidance for scholars, planners, and policymakers aiming to understand and co-produce context-sensitive, just, and adaptive pathways towards sustainable urban futures. This book is intended for scholars, advanced graduate students, and critically engaged practitioners in the fields of urban planning, sustainability studies, human geography, and environmental governance. It will be of particular interest to those conducting research on urban transitions, planning theory, climate adaptation, and socio-ecological transformation. The volume is especially suited for postgraduate courses and seminars on sustainable urban development, strategic spatial planning, and critical approaches to environmental policy, governance, and justice. The Open Access version of this book, available at http://www.taylorfrancis.com, has been made available under a Creative Commons [Attribution-Non Commercial-No Derivatives (CC BY-NC-ND)] 4.0 license