The War of the World, by Niall Ferguson

This is the book of a six-part television series for Channel 4, and it has both virtues and vices of its genre. Niall Ferguson benefited from the research of many assistants, as he acknowledges; but apart from a short list of archives and a long bibliography, he provides no references. He surveys immense swathes of territory, but his coverage is more episodic than panoramic. He makes eye-catching pronouncements but all too often they don't bear scrutiny: he credits Mussolini, a weak dictator, with establishing "the first truly totalitarian regime".

Most dramatically, Ferguson sets out a thesis: that the 20th century, the "age of hatred", was "far more violent in relative as well as absolute terms than any previous era". Yet not only does he fail to substantiate it, but he adds a late appendix conceding that the last century was "not so uniquely bloody" after all.

As he shows in this inconsistent postscript, even with superior technology modern mass murderers could hardly match the achievements of barbarians, crusaders, colonialists and civil warriors. China's Taiping rebellion alone annihilated more people than the First World War. Pol Pot was responsible for two million deaths in Cambodia, but at least seven million died in King Leopold's Belgian Congo. The Second World War killed 59 million, 2.6 per cent of the world's population; Genghis Khan, who killed 37 million, reduced it by a tenth. He habitually butchered all the inhabitants of cities in his path - 1.6 million in Herat, about six times the number massacred during the Japanese "Rape of Nanking".

So in the last pages, Ferguson revises his grand claim. Instead of asserting that the last century saw the world's bloodiest organised slaughter, he says "it witnessed a transformation in the kind of war waged by developed Western societies against one another". Its further unique feature is that "the leaders of apparently civilised societies were able to unleash the most primitive instincts of their fellow citizens".

Here he is on more solid, if less original, ground. And his account of the internecine struggles between and among the great powers, mainly from the Boer War to the Korean War, reveals him at his best. His descriptions of atrocities will purge readers with pity and terror. He fixes on compelling details: no sooner had the Soviets seized Buchenwald than they used it to house their own prisoners.

His judgements are usually incisive. Unlike other right-wing historians, he censures Chamberlain's attempts to appease Hitler. Ferguson maintains convincingly that Britain and France should have gone to war in 1938, when Germany was weak and Russia might have joined Czechoslovakia to form a strong eastern front. Similarly, he dismisses the notion that Churchill might have saved the British Empire by negotiating a separate peace with Hitler. After all, as Stalin discovered, the Führer could not be trusted.

Ferguson's statistics are copious and telling. During the Second World War four Western soldiers were captured for every one killed in the Pacific; one Japanese was captured to 40 killed. During a conventional bombing raid on 9 March 1945 almost 100,000 citizens of Tokyo were, in General Curtis LeMay's words, "scorched and boiled and baked to death". General Motors provided a tenth of all US war production and Ford manufactured more military equipment than Italy. For every additional 19 tons of steel produced during the Stalinist period, one Soviet citizen perished. Ferguson might have noted, for comparison, that in 1800 two tons of Caribbean sugar cost the life of one slave.

He is surprisingly fallible, though, for someone who made his reputation as an economic historian. German workers did not become much "better off" between 1933 and 1939, as Richard Evans shows. Countries with the largest empires were not necessarily "best able to withstand the Depression" - France, with colonial possessions second only to Britain's, suffered an "economic Sedan". It is wrong to say that "the British Empire became truly popular only in the last half-century of its existence". Except during a brief late-Victorian/Edwardian interlude, Britons remained "absent-minded imperialists".

Ferguson attributes 20th-century violence, including the hundred major conflicts between 1945 and 1983 which resulted in 19 million deaths, to three main factors. These are ethnic rivalry, economic volatility and empires in decline. Yet such broad explanations hardly go to the heart of the matter. From time immemorial people have killed each other for any reason and none. Ferguson seems to recognise this, though it undermines his argument. Towards the end he quotes Freud, who told Einstein that the human "instinct to destroy and kill" was perennial. It was the antithesis of the erotic instinct "to conserve and unify". There was no point protesting against war, Freud concluded bleakly, for it was both natural and unavoidable.

Piers Brendon's 'The Dark Valley' is published by Pimlico