No year of the war saw so much change in allied fortunes as 1918. The trauma of Passchendaele in the summer of 1917 was followed by a bleak winter with little prospect of victory. There was then the spectre of defeat when the spring offensive from late March 1918 brought German forces within fifty miles of Paris. Yet after a month of bitter fighting, the German army was exhausted and the allies were on the brink of a decisive advance leading to victory – snatched from the jaws of defeat – in November. The USA had entered the war in April 1917 but the relatively small number of troops it sent from the summer of 1917 had little initial impact. That changed in the early summer of 1918.