This new handbook provides a platform to bring together multidisciplinary researchers focusing on greening high-density agglomerations from three perspectives: climate change, social implications, and people's health. Written by leading scholars and experts, the chapters aim to summarize the "state-of-the-art" and produce a reference book for policymakers, practitioners, academics, and researchers to study, design, and build high-density cities by integrating green spaces. The topics covered in the book include (but are not limited to) Urban Heat Island, Green Space and Carbon Sequestration, Green Space and Social Equity, Green Space and Public Health, Biophilic Cities, Urban Agriculture, Vertical Farms, Urban Farming Technologies, Nature and Biodiversity, Nature and Health, Biophilic Design, Green Infrastructure, Urban Revitalization, Post-Covid Cities, Smart and Resilient Cities, Tall Buildings, and Sustainable Vertical Cities.