Starting from the top-level system design of computing networks, this book introduces the core functions of computing networks and then elaborates on key technologies around the functions of the computing network brain. Chapters 1 and 2 provide an overview of the development background and trends of computing network technologies, along with an in-depth discussion of the relationship between computing networks and cloud networks. Chapter 3 systematically introduces the architecture of computing networks. Chapter 4 discusses the operational and transactional technologies of computing networks. Chapters 5 to 9 comprehensively explain the core functions of the computing network brain, including integrated orchestration, management and scheduling, intelligent operation and maintenance, intelligent engine, and digital twin of computing networks. Chapter 10 explores the application scenarios of computing networks, and Chapter 11 is an outlook on computing networks’ future development.