Depictions of totalitarianism in fiction, a form of government and a political system that prohibits all opposition parties, outlaws individual and group opposition to the state and its claims, and exercises an extremely high if not complete degree of control and regulation over public and private life. It is regarded as the most extreme and complete form of authoritarianism. In totalitarian states, political power is often held by autocrats, such as dictators (totalitarian dictatorship) and absolute monarchs, who employ all-encompassing campaigns in which propaganda is broadcast by state-controlled mass media in order to control the citizenry. As a political ideology in itself, totalitarianism is a distinctly modernist phenomenon, and it has very complex historical roots. Philosopher Karl Popper traced its roots to Plato, Georg Wilhelm Friedrich Hegel's conception of the state, and the political philosophy of Karl Marx.