Sandwiched between the better-known Battles of the Somme and Passchendaele, the Battle of Arras has scarcely received the attention it deserves. It was an important battle on several levels. It was conceived and fought in support of the French effort to win the war with one gigantic offensive initially targeting the Chemin des Dames. Preparations for it were sidetracked by the replacement of French Commander-in-Chief Joffre by General Robert Nivelle and the unsuccessful attempt by Prime Minister Lloyd George to subordinate Field Marshal Haig and the BEF to the new French C-in-C. Preparations were further slowed down by inter-allied disagreements over the sharing of railway facilities, BEF takeover of French-manned sectors of the Front and the appalling weather of the worst winter of the war. They were further thrown into confusion by the German decision to withdraw to the newly constructed Hindenburg Line, thereby not only conserving manpower but also forcing the Allies to maintain contact by advancing uncertainly over ground laid waste and booby-trapped. When the British finally attacked on 9 April 1917, that day proved to be the most successful of the war to that date for the BEF. The First Army’s Canadian Corps all but completed the capture of the allegedly impregnable Vimy Ridge and the Third Army advanced further in one day than had ever previously been achieved. It would not last. The attack lost momentum and the Germans quickly began to recover from their early shocks. It proved more difficult than had been expected to capture and cling on to Monchy-le-Preux; the Fifth Army, launching its operation to capture Bullecourt village to assist Third Army’s main thrust, found itself embroiled in a bitter struggle that would extend over the following five weeks. Over the course of the same period the First and Third Armies renewed their assaults on several occasions with the gains, if any, counted only in yards. The author has examined in some detail the political, military and inter-allied aspects of the lead up to the Battle. He has then looked closely at the BEF and French plans and operations within the framework of the Battle of Arras and the Second Battle of the Aisne (Chemin des Dames). He evaluates the performances of the involved Allied armies and their leaders. Finally he looks at their careers and lives following the events of April-May 1917.