The First World War had a profound impact on British society and on British relations with continental Europe, the Dominions, the United States and the emerging Soviet Union. The pre-war world was transformed, and the world that we recognise today began to take shape. That is why, 100 years after the outbreak, the time is right for this collection of thought-provoking chapters that reassesses why Britain went to war and the preparations made by the armed forces, the government and the nation at large for the unprecedented conflict that ensued.