This book offers an exploration of how cities can become engines of equity and well-being. As urbanization accelerates globally, this book argues, the future of truly sustainable, resilient cities depends on making them more equitable by design. It begins by recognizing that while cities are powerful hubs of economic activity and innovation, they often reinforce social and spatial inequalities—manifested in uneven access to housing, infrastructure, and opportunities. Drawing inspiration from biological systems that optimize for collective resilience, the book contrasts this with urban systems that currently prioritize wealth accumulation over equitable distribution. Instead of accepting this as status quo, the book proposes a new, forward-looking approach: a normative-scientific framework for measuring spatial inequalities and accessibilities within cities to inform the planning of cities for human well-being. By introducing concrete metrics and scaling tools, the book aims to support the design and planning of cities grounded in Amartya Sen’s capability approach—cities that enable all residents to lead fulfilling lives, regardless of their economic position.