In the aftermath of recent popular uprisings in dictatorships, many observers argued that information and communication technologies, notably the Internet, played a key role in the mobilization of political protest. This book unpacks when and under which circumstances Internet technology can benefit opposition activists aiming to mobilize protests, and when the technology plays into the hands of autocratic governments. Since autocratic governments enjoy a high degree of control over the introduction and expansion of Internet technology and over digital communication ows, the book argues that it should help them keep levels of protest low in the long-term. However, once protest has started, short-term government intervention becomes more difficult, which is why Internet technology can catalyze ongoing episodes of unrest. The book presents detailed empirical analyses of the relationship between the use of Internet technology and protest in autocracies. By leveraging new sub-national data on political protest and Internet penetration, these analysis cover more than sixty autocratic countries at the level of cities. The results show that higher levels of Internet penetration in cities reduce the overall occurrence of protest in dictatorships, but once protest has started, the Internet contributes to the continuation of protest in the same city as well as its diffusion to other locations. By examining the use of the Internet by governments in relation to other means of autocratic repression, the book also demonstrates the technological modernization of autocratic politics, where digital repression via the Internet partly substitutes traditional forms of political control.