The creation of the Supreme War Council and the change of Chief of the Imperial General Staff in late 1917 and early 1918 respectively, ensured that the final step towards Allied unity of command was easier to accept in high-level British political and military circles. With the commencement of the great German spring offensive on 21st March 1918, the necessity for a “Supreme Commander of the Allied Armies” became patent, and Field Marshal Sir Douglas Haig readily accepted celebrated French General Ferdinand Foch (1851-1929) in that role. However, when a second German offensive was launched against the British lines in Flanders, Haig became anxious then angry about Foch’s refusal to relieve hard-pressed British and Dominion troops in that strategically vital sector. Accordingly, he demanded the appointment of a senior British officer to act in an official liaison role with the Allied high command. Lieutenant-General Sir John Philip Du Cane (1865-1947) was such an officer. Already well-known to Prime Minister David Lloyd George and senior members of his coalition government, Du Cane’s intelligence and his “equable” temperament made him a suitable candidate to act as liaison to the recently created Allied generalissimo. Remaining at Supreme Allied Headquarters from April to November 1918, Du Cane continued in his liaison role throughout 1919. It was during this period that he wrote a personal account and collected related documents here published in one volume for the first time. Includes an extended introduction by editor and translator Elizabeth Greenhalgh.