This chapter outlines the significance of the digital revolution for International Relations. The first section establishes the political context that shaped the development of the internet, showing how this informed both its technical building blocks and modes of governance. The second section explains how these new technologies also entailed a distinct set of vulnerabilities. In doing so, it highlights the emergence of cybersecurity as an issue of national security, including the potential for cyber warfare between states. The third section introduces the politics of social media platforms that have enhanced pro-democracy movements such as the Arab Spring, but also driven polarisation, fostered extremism and been harnessed by a range of actors, from terrorist groups and intelligence services through to diplomats and even heads of state. The final section tracks the rise of internet sovereignty, which began in the early 2000s and has since become a significant international political tension point. We highlight how some states have sought to control information within their geographical borders, and use online censorship, propaganda and surveillance to govern their populations.