Ferdinand Foch ended the First World War as Marshal of France and supreme commander of the Allied armies on the Western Front. Foch in Command is a pioneering study of his contribution to the Allied victory. Elizabeth Greenhalgh uses contemporary notebooks, letters and documents from previously under-studied archives to chart how the artillery officer, who had never commanded troops in battle when the war began, learned to fight the enemy, to cope with difficult colleagues and allies, and to manoeuvre through the political minefield of civil-military relations. She offers valuable insights into neglected questions: the contribution of unified command to the Allied victory; the role of a commander's general staff; and the mechanisms of command at corps and army level. She demonstrates how an energetic Foch developed war-winning strategies for a modern industrial war and how political realities contributed to his losing the peace.