Short answers, pulled from the story.
Autocracy is a form of government in which absolute power is held by one person. It is contrasted with democracy and other forms of free government by the autocrat's unilateral power to repress civil liberties and determine what freedoms, if any, citizens may exercise.
Autocracies are classified as totalitarian or authoritarian. Totalitarian governments demand active ideological participation and do not allow political or cultural pluralism; communist states and Nazi Germany are historical examples. Authoritarian governments maintain control through repression without mandating adherence to a state ideology, and include most monarchies, military dictatorships, and theocracies. Sub-types include despotism, sultanism, and various hybrid regimes.
Most autocratic governments are overthrown by a coup, usually with internal support from elites who decide it is no longer in their interest to back the autocrat. Overthrow through popular revolt alone is virtually nonexistent throughout history. Popular support for democracy is a significant indicator of pressure on autocratic regimes, and revolts are most likely to occur during periods of reform.
Autocracy derives from the Ancient Greek autos, meaning self, and kratos, meaning power or might. The combined form became the Byzantine Greek autocrator and the Latin imperator, both titles for the Roman emperor. The term was later adopted into Russian as samoderžec and then translated into French and German variants before evolving into a general descriptor for any absolute ruler.
Modern dictatorship became more common in the 19th century, beginning with the caudillos of Latin America and the empires of Napoleon and Napoleon III in Europe. Totalitarian dictatorships developed in the 20th century with fascist and communist states, particularly during the interwar period and the Great Depression.
Autocratic rule has measurable effects on a country's politics long after it transitions to democracy. Citizens of postcommunist nations are more likely to distrust government and free markets. Xenophobia is generally more common in post-autocratic nations, and voters there are more likely to support far-right or far-left political parties.