‘The characteristic feature of the crisis of the twenty years between 1919 and 1939 was the abrupt descent from the visionary hopes of the first decade to the grim despair of the second, from a Utopia which took little account of reality to a reality from which every element of Utopia was rigorously excluded… The Utopia of 1919 was hollow and without substance,’ So wrote E. H. Carr in the conclusion to his Twenty Years Crisis, which he sent to the press in the middle of July 1939. Fifty years later one cannot but agree with him that the peace settlement of 1919 ‘failed’: Hitler, Mussolini and Stalin wiped it off the map of Europe. But though the Second World War created a very different ‘realistic’ world, some of the ‘Utopian’ ideals of 1919, so brusquely dismissed by Carr, re-surfaced irrepressibly after 1945, and some of their practical applications returned to the agenda of international politics.