John Keegan chronicles the 1944 invasion of Normandy, showing each of the title’s six armies in a battle sequence testing them to the utmost: 1) the Americans in their night drop on the eve of the landings, 2) the Canadians in action at the Omaha beachhead, 3) the English fighting their way inland, 4) the Germans in their surprisingly strong resistance, 5) the Poles in exile blocking the German escape route, 6) the French liberating at last the City of Light.