With the advent of the digital age, gaining insight into the characteristics and trends of early-stage interactions and development among nations has become a hot topic and frontier area in the discipline of international relations. Deepening the understanding of the impact of digital technology on international politics has become an important research direction in international relations. This book is originated from the attention given to the digital age by the Institute of International Relations at Tsinghua University since 2018 and the research and exploration carried out around the early-stage international/regional order, international security competition, and foreign strategic choices in the digital age initiated in 2020. The book primarily analyzes the changes and continuities of great power strategic competition and international/regional order as the world enters the digital age, along with their impact mechanisms. It combines real-world international relations scenarios to reveal the shaping and influence of digital technology on national military capabilities, international security competition, and the evolution of international security norms. Building on this foundation, it describes and analyzes the strategic choices of countries in the process of digital technology competition and their influencing factors, presenting numerous research findings with theoretical insights and practical significance.