The Nazi regime did not create an 'empire' in its traditional form of an accumulation and exploitation of overseas territories, but instead it occupied and subjugated its European neighbours.

By the end of 1942, Hitler and his henchmen controlled almost one third of the lands of Europe and nearly half of its population. To put this into its proper perspective - only Napoleon had previously managed to achieve such massive domination.

Hitler's original idea of a 'greater' Germany was to provide more Lebensraum (living space) for the German people by breaking down the borders with its near neighbours, Poland and Czechoslovakia.

But this project soon expanded to include Grossraum (great space) and inevitably involved establishing hegemony over other European races.

As the Reich grew and the power base increased, the Nazi theorists began to disagree about how this 'empire' should be administered and the resulting chaotic ineptitude helped precipitate their final downfall.

Much of the administrative responsibility was handed to head of the SS, Heinrich Himmler, who devoted a huge amount of his energy into formulating plans for deportations, the destruction of various populations or their 'Germanisation.'

But, blinded by racial obsessions and prejudices, Himmler and his vast clerical staff implemented an array of measures that were not only unworkable but also without a shred of common sense.

As Mazower argues in his powerful reassessment, Hitler's critics from within his own party were proved right. 'Germany could have racial purity or imperial domination but it could not have both,' they said.

As the orgy of destruction and killing continued unabated, and more and more Germans were called up to fight, it began to dawn on some Nazis that 'they might have conquered too much land' and that 'the Reich might turn out to be short of people after all.'

The anomaly was that by 1944 Germany was completely dependent on foreign workers while in SS-run labour camps, a workforce of 1.65 million people was being whittled away by starvation.

Werner Best, an SS administrative theorist, did not want to enslave what he considered 'inferior' races but instead believed they should be allowed to develop their own institutions.

But Himmler and Heydrich were jockeying for position and would not countenance a diminution of SS powers and Hitler himself refused to support self-determination for Baltic and Ukrainian nationalists.

And so, as Hitler's empire grew too big and too fast, the Reich began to degenerate into a series of personal power bases with imperial policies created on the hoof and the military mired in the exigencies of war.

Thus Hitler's aspirations to build a Germanic 'empire' were foiled by his innate provincialism, his lack of foresight and his obsession with the extermination of 'inferior' races. As Mazower points out: 'All that counted in his view was to be feared and obeyed.'

This is a sweeping, forensically thorough and immensely scholarly interpretation of the events that left Germany dismembered and a continent permanently scarred.

The empire that sought to find its salvation through the death of millions was eventually consumed by its own moral and intellectual bankruptcy - leaving only death in its wake.

(Allen Lane, hardback, £30)