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 of its men, 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? Macmillan is a previous winner of the Samuel Johnson Prize and won the International Affairs Book of the Year at the Political Book Awards 2014 for this book. Chaired by Nik Gowing.