This introductory chapter establishes the book’s central focus on designing cities that foster health, equity, and sustainability. It emphasises the urgency of addressing the twin crises of rapid urbanization and climate change by placing the well-being of people and the environment at the forefront of urban development. This chapter presents a unified strategy for tackling the issues facing modern cities by fusing environmental sustainability, urban planning, and public health. With a particular focus on creating healthy and sustainable urban environment, the chapter provides an overview of how climate-resilient urbanism can turn urban areas into ecosystems that are inclusive, adaptable, and conducive to human health. It points out obstacles like resource disparities and policy inertia while suggesting actionable solutions like participatory governance and community-driven practices. The chapter highlights how rethinking cities as places where resilience and well-being are prioritized has the potential to be transformative and catalytic of wider sustainable development outcomes. This introduction provides a conceptual framework that encourages readers to envision and implement strategies for building cities that prosper in the face of global challenges by laying the groundwork for the book’s in-depth analysis and practical case studies.