The first total war of the twentieth century lasted four and a quarter years. It covered almost the whole continent of Europe and theatres in the Near East and Africa, not to mention the high seas. It involved many millions of fighting men, claimed some eight million lives, engaged the economies of all the belligerent countries to an unprecedented degree, cost more than it had been thought any country's finances could bear, and introduced political and social upheaval. Europe bore the main brunt of the fighting, the casualties, the damage, and the direct and indirect costs: the task of reconstruction therefore mainly concerned Europe. The war also speeded the development of a trend that had started well before 1914, the growth of major centres of political and economic power outside Europe, above all in the United States. This development affected the task of reconstruction and helped to determine international economic (and to a lesser extent political) relations for the whole of the interwar period.

Later experience suggests that the task of reconstruction after the First World War was generally underestimated and misunderstood. This should not be particularly surprising. There were no precedents; the pre-1914 international system did not provide useful tools; the new political order being devised as a result of the war provided some fresh ideas, but it was not universally accepted. Europe did recover from the First World War, but unevenly; and some of the means used enhanced later difficulties.