The Burning Tigris by Peter Balakian

In the summer of 1915, Leslie Davis was American consul in Harput, a remote town in the central Anatolian highlands, three weeks' ride on horseback from Constantinople.

In the summer of 1915, Leslie Davis was American consul in Harput, a remote town in the central Anatolian highlands, three weeks' ride on horseback from Constantinople. About a third of the population in the region were Armenians - villagers, farmers, merchants and teachers - who had always got along with their Turkish neighbours. But, a few months into the Great War, the government ordered Armenian schools to close, and arrested leading men. In July, town criers publicised their imminent deportation, street by street; and homes and properties were pillaged. A couple of months later, after the deportations, Davis rode out into the surrounding countryside, leaving early so as not to be noticed.

By the side of the road shallow graves betrayed human remains, and villages once inhabited by Armenians lay in ruins. As he reached the side of a local lake, he peered down from the path above and saw hundreds of bodies in its waters. Neighbouring ravines contained thousands more. On a remote part of the lake shore, he came across hundreds of corpses piled in rows. It was, he wrote, as if "the world were coming to an end".

Although successive Turkish governments have tried to deny what was done to the Armenians, the killing was a messy business and there were no top-secret extermination sites such as were built by the Nazis in Poland. The genocide was a relatively public affair, and US missionaries, German businessmen, railway engineers and even foreign soldiers in Ottoman service all sent graphic despatches home. The atrocities were outlined in newspaper headlines, and the old Gladstonian, Lord Bryce, compiled a still-useful report for the British government. We will never know for sure, but probably between 800,000 and one million people were killed or starved to death.

The horror of it all emanates vividly from the pages of Peter Balakian's new history. The sheer scale of the massacres has an overwhelming impact and his access to the accounts of survivors and diplomats, and his understanding of Armenian culture and society, help bring to life the world that was lost with the victims. It quickly becomes clear that the Holocaust was not the first such onslaught on an entire community; indeed, the parallels with that event are frequently underlined.

Like other commentators, Balakian believes genocide can offer lessons. He stresses the ethical challenge state-sponsored violence on such a scale poses to bystanders and foreign powers, and underlines the heroic response of those who tried to end the killing - activists, relief workers and idealists who mobilised local funds of sympathy and did what they could.

A sub-theme of the book - a parable for the present? - is how these events resonated in the US. Calls for the country to live up to its "duty to civilisation" by intervening led to the usual tussle between realpolitik and the politics of compassion. President Woodrow Wilson never declared war on the Ottoman Empire but did support the idea of an American mandate for an independent Armenia; it failed to get through Congress.

Balakian does not bother to hide where his sympathies lie - with those who cared, against the isolationists and hard-nosed men who believed national interest trumped moral imperatives. But his sympathies run deeper than that, for the way he tells it this was a story of good and evil, of Armenians against Turks, Christians attacked by Muslims, blameless victims against malevolent perpetrators led by psychopaths such as Sultan Abdul Hamid.

He describes a tradition of state-sponsored violence in Turkey that starts with the massacres of the mid-1890s (which themselves killed more than 100,000 people) and 1909 (about 15,000), and continues, in a sense, to this day through the denial itself.

Only it was a bit more complicated that that. Reading Balakian, one would not know that in 1912 the Sultan's foreign minister had been an Armenian, nor that the Young Turks, who instigated the genocide, co-operated with Armenian parties up to the start of the First World War. There was a centuries-old policy of co-operation between the Porte and the Armenian community which only the rise of nationalism - Armenian and Turkish - eroded.

In Constantinople, the Armenian Patriarch preached loyalty to the sultan. But Armenian revolutionaries sought autonomy for the Armenian provinces of Anatolia by forcing Great Power intervention, and were even willing to provoke Ottoman repression to get there. Call it the Kosovo strategy: it had worked for Christian nationalists in the Balkans, and it looked to some it might work for the Armenians, too.

Balakian cannot bring himself to criticise these activists. The most he will say is that they were naïve. Russian diplomats did indeed force the empire to accept foreign oversight of the Armenian provinces in early 1914. Bitterly opposed in Constantinople as the first step to secession, the agreement, abandoned when war broke out, encouraged the Ottomans to see the Armenians as a Russian fifth-column.

Nor had Christians always been the victims, Muslims the perpetrators. Bal- akian's heroic American Protestant missionaries were not neutral observers but agents of radical social and cultural change trying to transform the Ottoman empire. Meanwhile, largely unnoticed by the Western humanitarian conscience, a tidal wave of Muslim refugees, well over one million, fled into Anatolia from Russia and the Balkans after 1860: a reminder of the human consequences of Ottoman decline.

After 1908, Bosnia, Crete, Albania and Macedonia were all lost, too. By spring 1915, Russian troops threatened Anatolia from the east, and the British seemed about to seize Constantinople: the empire faced dismemberment. None of this in any way justifies what happened to the Armenians, but it underlines the existential crisis that faced the empire's young and arrogant leadership, humiliated on the battlefield, their grand strategy in ruins.

In 1919, under Allied pressure, a postwar Ottoman government set up tribunals to investigate the Armenian murders. But in the East the war was not really over: Armenian fighters were trying to set up an independent state - from the Black Sea to the Mediterranean, ran the dream - while Mustafa Kemal formed an association to stop them. The Armenians gambled on foreign support they did not have, while Kemalists built an army against them. Having neutered the Russian threat by alliance with the Bolsheviks, Kemal's men routed the Armenians, expelled the Greeks from Asia Minor, and got rid of the ruling family, too.

The tribunals were abandoned, a Turkish republic arose from the ashes of empire, and ever after, Ataturk's heirs insisted that the Armenians had brought their misfortunes on themselves. The Burning Tigris remains, understandably enough, a work of denunciation. Even so, more than denunciation will be needed to help us make sense of what happened.

Mark Mazower, professor of history at Birkbeck College London, will publish 'Salonica, City of Ghosts' (HarperCollins) this summer