The beginning of the twentieth century saw human civilization at its most enlightened, well-educated, globalized and wealthy. What turned it into a bloodbath?

Niall Ferguson re-tells the story of history's most savage century as a continual war that raged for 100 years. From the plains of Poland to the killing fields of Cambodia, he reveals how economic boom-and-bust, decaying empires and, above all, poisonous ideas of race led men to treat each other as aliens. It was an age of hatred that ended with the twilight, not the triumph, of the West. And, he shows, it could happen all over again.