Radiology is increasingly recognized as a key contributor to the environmental footprint of healthcare due to high energy consumption, single-use materials, and contrast media waste. At the same time, radiology is also well-positioned to lead the transition toward more sustainable practices. This introductory chapter explores the intersection between artificial intelligence (AI) and sustainability in radiology. It provides an overview of environmental challenges in current imaging practices and introduces AI as a strategic enabler for improving energy efficiency, workflow optimization, and resource stewardship. The chapter also outlines the structure of the book, which brings together scientific insights, technical strategies, operational measures, and policy frameworks. Although not all practices described are fully evidence-based, the chapter aims to raise awareness, stimulate practical action, and support hospitals and radiology departments in integrating sustainability into their daily operations. This framing sets the stage for the subsequent chapters, which examine sustainability from technical, clinical, ethical, and institutional perspectives.