This introductory chapter provides the foundation for understanding energy transitions in East Asia, where economic growth and fossil fuel dependence present significant challenges to decarbonization. The chapter outlines the global urgency for a low-carbon transition and frames the book’s exploration of key regional, sectoral, and national dynamics. It justifies the structure of the book, which is divided into four parts: global and regional drivers of energy transition, sector-specific applications, regional and national case studies. This structure reflects the complexity of energy transitions and the need for tailored approaches. Finally, the chapter synthesizes key insights, emphasizing the role of policy, regulation, technological innovation, and regional collaboration in achieving carbon neutrality. It highlights the importance of ensuring that energy transitions are equitable and aligned with the unique socio-economic contexts of East Asia, offering strategic pathways for overcoming geopolitcal, technical, financial, and policy barriers.