This book delivers cutting-edge research focused on reducing energy consumption across computing systems while maintaining performance and scalability. It presents novel methods and architectures that advance the field of sustainable and green technologies. Contributions span topics such as low-power algorithms, green cloud infrastructures, energy-aware IoT systems, and intelligent optimization techniques. Selected from the best papers of SCGT'2025, each chapter offers deep technical insights and practical applications. Aimed at researchers, engineers, and system designers, this book is a valuable resource for building environmentally sustainable computing infrastructures.