Book excerpt: The City is an Ecosystem maps an interdisciplinary, community-engaged response to the great ecological crises of our time—climate change, biodiversity loss, and social inequality—which pose particular challenges for cities, where more than half the world’s population currently live. Across more than twenty chapters, the three parts of the book cover historical and scientific perspectives on the city as an ecosystem; human rights to the city in relation to urban sustainability; and the city as a sustainability classroom at all educational levels inside and outside formal classroom spaces. It argues that such efforts must be interdisciplinary and widespread to ensure an informed public and educated new generation are equipped to face an uncertain future, particularly relevant in the post-COVID-19 world. Gathering multiple interdisciplinary and community-engaged perspectives on these environmental crises, with contemporary and historical case study discussions, this timely volume cuts across the humanities and social and health sciences, and will be of interest to policymakers, urban ecologists, activists, built environment professionals, educators, and advanced students concerned with the future of our cities.