The Triumph of the Dark is the second volume in Zara Steiner's gargantuan history of international relations between the wars. The first book, The Lights That Failed, first published in 2005, took the story from 1919 up to January 1933, when Hitler became chancellor of Germany. The Triumph of the Dark deals with the years when postwar history was coming to an end and pre-war history about to begin. It is a story, Steiner writes, with "few heroes, two evil Titans and an assortment of villains and knaves. I have not enjoyed their company."
Taken together, the two volumes are a remarkable achievement of conscientious scholarship. To write the diplomatic history of the interwar years is to enter a thick jungle, if not a swamp, and Steiner has done well not to be overwhelmed by her sources. She has delved deeply into all of the disputed issues of the 1930s; her judgements are weighty and, by contrast with so many other books on the period, she analyses the policies of the smaller states of Europe as well as those of the great powers.
But the book is tough-going, overloaded with facts and top-heavy with detail. It could have done with judicious selection and pruning. It is, moreover, old-fashioned international history, barely discussing the ideological and sociological forces lying behind diplomacy. The best diplomatic history, and especially that of the 1930s, deals with the grandest of themes - war and conflict, the existence and destruction of communities and civilisations. Yet The Triumph of the Dark is almost all foreground; there is far too little background.
The central theme - the growing dominance of Hitler - is announced at the very beginning of the book. The conclusions are on the whole conventional, and similar to those reached by Donald Cameron Watt in his book How War Came, published in 1989. Hitler, Steiner believes, was the only leader who sought war without reserve in 1939, and his will and power were sufficient to overcome the wishes of the many others who sought to prevent it. But perhaps matters were not quite so clear-cut.
Everything that we have learned about the Nazi regime in recent years - synthesised in Ian Kershaw's remarkable, two-volume biography Hitler - confirms that it expressed, in violent form, the outlook and wishes of many, perhaps most, of the German people. Indeed, that was the source of Hitler's power, and explains why so many were willing to obey the tyrant for so long. He emphasised and accelerated powerful trends already present in German society. He did not create them.
A J P Taylor used to tell the story of meeting the great Dutch historian Pieter Geyl late one evening in Whitehall. After confessing that he had just committed a sin against historical scholarship by attending a dinner in honour of Arnold Toynbee, Geyl, who, although not Jewish, had suffered in a German concentration camp, told Taylor that his Origins of the Second World War was a wicked book for implying that the Nazis were little different from other Germans. "But was it true?" Taylor inquired. "You should not have said it," Geyl retorted.
Recent scholarship has tended to confirm Taylor's insight by showing the extent to which the Wehrmacht and the German foreign office were involved in atrocities. Nor was the Wehrmacht always backward in urging Hitler on to aggressive policies. The Nazi regime was a new kind of dictatorship, based on widespread popular support, and that is why it remains so frightening 65 years after its demise.
Steiner gives a sensitive account of the dilemmas faced in the 1930s by Britain and France, the only countries to go to war against Nazi Germany without having been attacked. She accepts that the options available to them were much narrower than most of their critics appreciated. The public, recalling the horrors of Verdun and the Somme, was unwilling to countenance great armaments, conscription, or any policy that might risk war. The politicians could not believe that a great and civilised country was being led, with the people's support, by a criminal lunatic. Hating war, they could not grasp that national socialism was based upon a glorification of war, and that, for this reason, appeasement had no chance of success.
But perhaps Steiner is wrong to concentrate the blame for the failure of British foreign policy on Neville Chamberlain. The ceding of the Sudeten German territories to Hitler in 1938 was not Chamberlain's personal policy, but that of the whole cabinet. Munich was the victory of a policy consciously pursued by the whole British government, and a victory also for those who had come to believe that troubles in Europe would be ended only if frontiers could be redrawn along national lines.
Chamberlain's diplomacy was designed not to circumvent the policy of his government, but to give effect to it and to avoid war, an aim in which he was, for a while, successful. His position was reinforced by the view of the chiefs of staff that Britain was in no condition to fight in 1938. It is a brave, perhaps reckless prime minister who ignores such advice. Nonetheless, by September 1939, when Hitler invaded Poland, both the British public and Chamberlain had concluded that stability in Europe could not be secured until Hitler had been destroyed.
That aim was eventually achieved, but at a terrible cost in human suffering. As Steiner points out, the war not only served to end the era of European predominance, it also called into question "the very concept of Europe as something more than a geographic expression". We are still living with the consequences.
The Triumph of the Dark: European International History 1933-1939
Oxford University Press, 1,130pp, £35
Vernon Bogdanor is a research professor at the Institute of Contemporary History, King's College London. His latest book is "The New British Constitution" (Hart, £17.95)