Dictatorship has, in one sense, been the default condition of humanity. The basic governmental setup since the dawn of civilization could be summarized, simply, as taking orders from the boss. Big chiefs, almost invariably male, tell their underlings what to do, and they do it, or they are killed. Sometimes this is costumed in communal decision-making, by a band of local bosses or wise men, but even the most collegial department must have a chairman: a capo di tutti capi respects the other capi, as kings in England were made to respect the lords, but the capo is still the capo and the king is still the king. Although the arrangement can be dressed up in impressive clothing and nice sets—triumphal Roman arches or the fountains of Versailles—the basic facts don’t alter. Dropped down at random in history, we are all as likely as not to be members of the Soprano crew, waiting outside Satriale’s Pork Store.

Only in the presence of an alternative—the various movements for shared self-government that descend from the Enlightenment—has any other arrangement really been imagined. As the counter-reaction to Enlightenment liberalism swept through the early decades of the twentieth century, dictators, properly so called, had to adopt rituals that were different from those of the kings and the emperors who preceded them. The absence of a plausible inherited myth and the need to create monuments and ceremonies that were both popular and intimidating led to new public styles of leadership. All these converged in a single cult style among dictators.

That, more or less, is the thesis of Frank Dikötter’s new book, “How to Be a Dictator: The Cult of Personality in the Twentieth Century” (Bloomsbury). Dikötter—who, given his subject, has a wonderfully suggestive, Nabokovian name—is a Dutch-born professor of history at the University of Hong Kong; he has previously written about the history of China under Mao, debunking, at scholarly length and with a kind of testy impatience, the myth of Mao as an essentially benevolent leader. “How to Be a Dictator” takes off from a conviction, no doubt born of his Mao studies, that a tragic amnesia about what ideologues in power are like has taken hold of too many minds amid the current “crisis of liberalism.” And so he attempts a sort of anatomy of authoritarianism, large and small, from Mao to Papa Doc Duvalier.

Each dictator’s life is offered with neat, mordant compression. Dikötter’s originality is that he counts crimes against civilization alongside crimes against humanity. Stalin is indicted for having more than 1.5 million people interrogated, tortured, and, in many cases, executed. (“At the campaign’s height in 1937 and 1938 the execution rate was roughly a thousand per day,” Dikötter writes.) But Stalin is also held responsible for a nightmarish cultural degradation that occurred at the same time—the insistence on replacing art with political instruction, and with the cult of the Leader, whose name was stamped on every possible surface. As one German historian notes, you could praise Stalin “during a meeting in the Stalin House of Culture of the Stalin Factory on Stalin Square in the city of Stalinsk.” This black comedy of egotism could be found even among neo-Stalinist dictators of far later date. In 1985, Nicolae Ceauşescu, Romania’s Communist leader, ordered up such television programs as “The Nicolae Ceauşescu Era” and “Science During the Nicolae Ceauşescu Epoch.” By law, his portrait was featured at the beginning of every textbook.

Dikötter’s broader point is that this manner spread to the most improbable corners of the world. His most interesting chapters, in some ways, are on the “tin-pot” dictators—like Duvalier, in Haiti, and Mengistu, in Ethiopia—who, ravaging poverty-stricken countries, still conform to the terrible type. The reason his subjects exhibit a single style is in part mutual influence and hybridization (North Korean artists made Mengistu a hundred-and-sixty-foot-tall monument in Ethiopia), and in part common need. All share one ugliness because all bend to one effect: not charm but intimidation, and not persuasion but fear.

The elements come together in almost every case to make one standard biography. There’s the rise, which is usually assisted by self-deluding opportunists who believe that they can restrain the ascendant authoritarian figure; old Bolsheviks like Grigory Zinoviev, countering Trotsky, played just as significant a role in Stalin’s ascent, largely through abstention, as the respectable conservative Franz von Papen did in Hitler’s. (“We can control him” is the perpetual motto of the soon-to-be-killed collaborator.) Next there is the attainment of power, and the increasingly frantic purging, followed by a cult of personality made all the more ludicrous by the passage of time, because it is capable only of inflation, not variation. Along with that comes some re-identification with figures from the national past. The exploitation of the imaginary Aryan history, bestrode by Valhallan gods, became central to the Hitler cult. In the same way, Dikötter shows, Duvalier took up the animism of Haitian vodou and presented himself as the avatar of the cemetery spirit Baron Samedi.

Then comes the isolation of the dictator within his palace—friendless and paranoid—and the pruning of his circle to an ever more sycophantic few. The dictator, rather than exulting in his triumph, withdraws into fearful seclusion. Finally, after all the death and brutality imposed, the dictator’s power, and often his life, ends with remarkable suddenness. You can watch video footage of Ceauşescu, in Bucharest, 1989, confidently addressing an assembled audience and realizing in a single moment that the crowd has turned. “Comrades! Quiet down!” the dictator cries out, while his wife shrilly shouts, “Silence!” The firing squad was only a few days away. Mussolini was ejected just as abruptly, and Hitler would have been, too, if he hadn’t killed himself first. Stalin seemed to make it to a natural end, but, as that terrific movie “The Death of Stalin” shows, he probably died sooner than he otherwise would have, because his flunkies were too terrified to do anything when they found him unconscious in a pool of his own piss.

Still, Dikötter’s portrait of his dictators perhaps underemphasizes a key point about such men: that, horribly grotesque in most areas, they tend to be good in one, and their skill at the one thing makes their frightened followers overrate their skill at all things, like children of a drunken father who take a small act of Christmas charity as proof of enormous instinctive generosity. Compare Dikötter’s account of Hitler’s rise with John Lukacs’s account, and one recalls how Lukacs, without softening the portrait one bit, recognized that Hitler did some things extremely well. Hitler’s occasional moments of shrewdness and even statesmanship—in seeing that Stalin would trust him not to invade Russia, or that France was not prepared to fight—made his followers more convinced than ever of his genius.

The difference between charismatic leadership and the cult of personality—different points in the trajectory of the dictator—is that the charismatic leader must show himself and the object of the cult of personality increasingly can’t show himself. The space between the truth and the image becomes too great to sustain. Mao, like God, could be credibly omniscient only by being unpredictably seen. Imposing an element of mystery is essential. And so most of the subjects here rarely made public appearances at the height of their cults. Stalin and Hitler both remained hidden for much of the war; to show themselves was to show less than their audiences wanted.