This is an essential work for understanding the dilemmas and possibilities of contemporary urbanism in the face of the environmental, social, and economic transformations shaping cities in the 21st century. With a critical, interdisciplinary, and current approach, the book investigates two of the main vectors of urban change: the growing adoption of sustainable practices in the real estate sector and the advancement of gentrification in large urban centers. Based on national and international case studies, robust theoretical analyses, and multidisciplinary references, this work examines the impacts of green buildings, environmental certifications (such as the LEED label), public sustainability policies, emerging urban technologies, and market instruments in shaping urban territories. At the same time, it reveals the social consequences of real estate appreciation and the displacement of vulnerable populations, proposing alternatives based on spatial justice, social inclusion, and the right to the city. Essential for researchers, urban planners, architects, public administrators, and students of geography, urban sociology, economics, and urban law, this book articulates theory and practice to reflect on smart cities, sustainable urbanism, socio-spatial exclusion, urban regeneration, social housing, housing cooperatives, and the role of technological innovations in reshaping the future of metropolises. With a clear structure and critical foundation, this book offers a comprehensive overview of the challenges and opportunities arising from the convergence of environmental sustainability and real estate market pressures, proposing paths toward a more ethical, balanced, and inclusive urbanism.