In the contemporary era of rapid technological advancements and ever-growing digital ecosystems, the intersection of cloud computing and sustainability has emerged as a pivotal concern for businesses, governments, and societies worldwide. "Sustainability in Green Cloud Computing- Theory and Techniques" aims to explore this critical nexus, providing a comprehensive guide to understanding and implementing sustainable practices within cloud environments. This book serves as an introduction to the themes, objectives, and structure of the book, setting the stage for an in-depth exploration of green cloud computing and its significance in promoting a sustainable future.