It is by far the best book yet published about the causes and origins of the second world war.
It throws a completely new and different light on what was happening in Western capitals as Hitler built up his armed forces for the war which broke out in 1939, and what comes out shows conclusively that those policies were policies not of appeasement but of active sympathy and support for Germany.
Dr. Leibovitz has delved deeply through a mass of letters, diaries and reports written by those most directly concerned and has traced the thread of a story that is still not understood by the general public, nor taken seriously by most of the academic world or contemporary political leaders.
We are now getting used to the publication of secret documents from the archives of the old Soviet Union and the revelations that receive the most attention are those which are designed to pour an unending stress of vilification on the communist regime and all its works.
But no comparable revelations are yet generally available that might throw an equally penetrating light on the activities of British ministers and diplomats as the Nazis and Fascists came to power in Germany and Italy.
The official account which we are all expected to accept is that, although Neville Chamberlain may have been a bit weak and rather slow to appreciate the full significance of the German military build-up, he was just a good and simple man of peace doing his best to avert war.
The truth is very different and this book brings it out in a way that is completely convincing, for it draws on all the sources to prove conclusively that there was a great deal of sympathy among the British establishment for what Hitler and Mussolini were doing.
Indeed the essence of the appeasement policy was to persuade Hitler to abandon any plans he might have for an attack on the Western Front and to give him a very broad hint - if not an outright assurance - that if he turned East he could have a free hand.
Seen in that light much of the responsibility for the war can be squarely placed upon the shoulders of the British government and those who survived that war ought to know how it came about.
The roots of the policy that was followed go back much further than 1932 or even further back than 1917 when the Russian Revolution occurred.
In an important passage in his book Dr. Leibovitz traces English history back to 1381 when the Peasants Revolt shook the King, through the English Revolution of 1649 which cost King Charles his throne and his head.
Since those events the ruling classes in Britain have always been alarmed at any sign of militancy by working people and this fear surfaced after the French Revolution and even more markedly after the overthrow of the Tsar in his winter palace in St. Petersburg.
Whatever the merits, or demerits, of the many years thereafter during which Communism was in power in Moscow, it is a plain and indisputable fact that the very existence of the USSR encouraged working people everywhere to throw of the shackles of colonial rule, and it inspired hopes in Britain too which were seen, at the top here, as being deeply threatening.
It is possible to argue - and I do - that the real anxieties in London were based, at root, on a fear, not of the Soviet generals but of the British people, who experiencing the deep slump in trade and industry could possibly have espoused socialism.
In that sense Hitler was seen as doing a very good job in destroying trade unionism, communism and socialism inside Germany and in constructing a military obstacle to any Soviet advance, and deserved discreet support.
Seen in that light it is clear that the Cold War itself did not start with the Berlin Air-lift in 1948 but can be traced back to the war of intervention in 1920 when an army was sent to crush the revolution.
And it is also becoming clear from the documents now available that even before the second world war - during which the USSR, the USA, Britain and France were allies - had officially ended, the Atomic bombs were dropped on Japan as a warning to Moscow that the West had acquired a weapon of overwhelming power.
If this analysis is correct, and I believe that it is, then almost all the propaganda to which we in the west have been subjected over nearly fifty years is false.
That conclusion would indeed be the inevitable consequence of glasnost in respect to our own political archives, were the capitals of western Europe and America to be as open as they now are in Moscow.
It also becomes painfully apparent, that, in the minds of many of the key figures in this story, the last world war was regrettably fought with the wrong ally and against the wrong enemy - an argument used by Rudolf Hess in May 1941 when he flew to Scotland hoping to get this message across.
The implications of this argument are enormous for those who lived through this period, but they also have a special relevance to the situation that exists in Europe today when Communism has disappeared, Germany is re-united and dominant, and the attempts to build a federal and highly centralized Europe would entrench that German power far more successfully than Hitler would have dared to hope.
Yet that is not the real end of the story for it is no co-incidence that the crisis of unemployment which has now hit western Europe and the United States is a product, at least in part, of the end of the cold war, in which the arms programmes kept capitalism going on a profitable basis, leaving it now without that prop.
The slump that has followed has re-created the fear and hopelessness that brought the fascists and nazis to power in the twenties and the thirties, and it may be that the recovery of a strong Germany and the parallel swing to the right that occurred in London and Washington in the eighties has also contributed to re-create the very conditions which Chamberlain hoped would develop.
However, liberated from the charge that all socialists in the west were secret agents of the KGB, the historical traditions of socialism inside the western countries are slowly re- asserting themselves free from the taint of having been financed by 'Red Gold', and objectively socialists now have the best chance for over forty years of seeing their analysis and policies win wider support.
This re-inforcement of socialist ideas may also have been strengthened by the return of the old-fashioned imperialism revealed in the Gulf War which has helped the non-aligned countries to an understanding of what the 'New World Order' is really about - namely the re-assertion of control by the rich industrial nations, amongst which Germany and Japan are two of the most powerful economically.
Dr. Leibovitz has therefore, in this book, done more than lay bare the evidence which helps us understand the past and has actually written a text that helps us to understand the present and the future.
For Germany does, indeed, now have a free hand in the East, Japan is the most influential country in the Far East, right-wing ideas are powerful again, and America and Britain may still have to pay a further price for the policies agreed at Munich and Berchtesgaden so many years ago.
But at least we have the benefit of this supreme work of scholarship to help us see that
it does not happen again.
Tony Benn
September 19 1992