From the back cover of the book:
The Last War Never Ended...
The Treaty of Thronehold stopped the massive march of armies across Khorvaire, but it didn't put an end to espionage, unrest, and border skirmishes among the nations of Eberron. And no treaty could ever end the horrors that haunt the dreams of every soldier, spy, and adventurer whose life was shattered by a century of warfare.
This supplement for the Eberron campaign setting presents everything you need to bring to the Last War to life in your Eberron game, whether you're playing a character who fought in the war or running adventures that take place during the century of conflict. New character options let you explore battlefield backgrounds, the magic of war, battle scars, and the benefits of working as a team. Campaign seeds help the Dungeon Master introduce the themes and events of the Last war in a current-day campaign or send characters back to their wartime days through flashbacks or actual travel through time. A comprehensive overview of the Last War provides all you need to know about the events, armies, battlefields, and themes of Eberron's greatest clash of nations.