What drives politics in dictatorships? Milan W. Svolik argues that all authoritarian regimes must resolve two fundamental conflicts. First, dictators face threats from the masses over which they rule - this is the problem of authoritarian control. A second, separate challenge arises from the elites with whom dictators rule - this is the problem of authoritarian power-sharing. Crucially, whether and how dictators resolve these two problems is shaped by the dismal environment in which authoritarian politics takes place: in a dictatorship, no independent authority has the power to enforce agreements among key actors and violence is the ultimate arbiter of conflict. Using the tools of game theory, Svolik explains why some dictators, such as Saddam Hussein, establish personal autocracy and stay in power for decades; why leadership changes elsewhere are regular and institutionalized, as in contemporary China; why some dictatorships are ruled by soldiers, as Uganda was under Idi Amin; why many authoritarian regimes, such as PRI-era Mexico, maintain regime-sanctioned political parties; and why a country's authoritarian past casts a long shadow over its prospects for democracy, as the unfolding events of the Arab Spring reveal. When assessing his arguments, Svolik complements these and other historical case studies with the statistical analysis of comprehensive, original data on institutions, leaders, and ruling coalitions across all dictatorships from 1946 to 2008.