The First World War followed a period of sustained peace in Europe during which people talked with confidence of prosperity, progress, and hope. But in 1914, Europe walked into a catastrophic conflict that killed millions, bled its economies dry, shook empires and societies to pieces, and fatally undermined Europe’s dominance of the world. It was a war that could have been avoided up to the last moment—so why did it happen? Beginning in the early nineteenth century and ending with the assassination of Archduke Franz Ferdinand, award-winning historian Margaret MacMillan uncovers the huge political and technological changes, national decisions, and just as important, the small moments of human muddle and weakness that led Europe from peace to disaster. This masterful exploration of how Europe chose its path toward war will change and enrich how we see this defining moment in our history.