HISTORIANS ALWAYS YEARN for closure, a date when their narratives can end, says Niall Ferguson in the introduction to his latest heavyweight work of narrative and analytical history, an examination of why the 20th century was the bloodiest yet.

In so yearning, historians also appear to want to package their history in marketable chunks. But does a century possess inherent significance? In fairness, although his book The War of the World is a tie-in with a coming Channel 4 series, Ferguson does not labour the matter. The popular historian also needs an arresting title for his book. Again, the author does not flog over much the H. G. Wells connection. But a television tie-in undoubtedly colours a book, even if it does not shape it. The pity, however, would be to see and perhaps dismiss The War of the World as a mere pendant to populist TV history. On the contrary, here is a work of originality and depth, history at its most challenging and controversial.

Why was the 20th century so violent, and why did its worst excesses occur in the early 1940s and in Central and Eastern Europe, Manchuria and Korea? Fergusons answer is ethnic conflict, economics and empires in decline. On the face of it, nothing new, but he digs deep into the foundations of received notions and comes to rather different conclusions from the usual. German anti-Semitism, for instance, was an extreme case of a general (though not universal) phenomenon. The principal distinguishing feature of the Holocaust was not its goal of annihilation but the fact that it was carried out by a regime which had at its disposal all the resources of an industrialised economy and an educated society.

It was the application of the nation-state model to Central and Eastern Europe, a complex patchwork of pales and diasporas, that increased the potential for conflict, these regions becoming the most lethal of the killing spaces of the 20th century. His exploration of race, both its scientific reality and its place in national myth, is a fascinating multidisciplinary analysis.

But why, if ethnic antagonism has been a constant of the human condition, has extreme violence occurred only at certain times? The answer, Ferguson says, is that ethnic conflict is correlated with economic factors. But again he suggests a rather different interpretation: it is not enough to look for times of economic crisis when trying to explain instability, for rapid growth in output and incomes can be just as destabilising as rapid contraction. It is, therefore, to economic volatility, that we must look  these violent punctuations having a bigger impact than long-running structural trend in prices and output.

But 20th-century violence, he maintains, is unintelligible if it not seen in its imperial context: the decline and fall of large multi-ethnic empires dominated the world in 1900. Nearly all the principal combatants in both world wars were empires or would-be empires. One of the reasons for this was again economic: economies of scale were available to an empire, as opposed to the nation state, in raising large armies and paying for them.

He points out that two of the greatest battles of the century — Stalingrad and El Alamein — were fought by “multi-ethnic forces under imperial banners”. Another reason was geographical: the points of contact between empires, the borderlands and buffer zones, or “the zones of strategic rivalry they compete to control”, see more violence than the imperial heartlands.

What Ferguson calls “the fatal triangle”, the territory between the Baltic, the Balkans and the Black Sea, was a vast killing space not just because it was ethnically mixed but because it was the junction of the imperia of the Hohenzollerns, Habsburgs, Romanovs and Ottomans. Manchuria and Korea occupied a similar position in the Far East, and with the rise in the critical importance of oil, so increasingly have the Gulf and the Near East.

The “ebbs and flows of international commercial integration” are closely associated with the rise and fall of empires, with war more prevalent at the beginning, and especially the end, of an empire’s existence. Twentieth-century empires were “exceptional in their capacity for dealing out death and destruction” because of “unprecedented degrees of centralised power, economic control and social homogeneity to which they aspired”. Indeed, they inherited from the 19th-century nation builders “an insatiable appetite for uniformity; in that sense they were more like empire-states than empires in the old sense”.

Perhaps most radically, Ferguson concludes that to see the 20th century as the triumph of the West, or the “American Century”, with its long, irreversible glide into liberal democratic capitalism (vide Francis Fukuyama’s “the end of history”), is “fundamentally to misread the trajectory of the past hundred years”.

What he sees is a reorientation of the world towards the East, which redresses a balance between West and East that had been lost in the four centuries after 1500. “No historian of the 20th century can afford to overlook this huge — and ongoing — secular shift,” he warns. If his reading of, in the words of the book’s subtitle, The Age of Hatred, is true, no one, not just the historian, can afford to overlook it.