After identifying the main issues relating to war, peace and social change in the 20th century, this book establishes the nature of European society as it was on the eve of World War I. A discussion of the armed forces available to the different governments also raises the question of how far the different armies represented microcosms of their own societies. Industrial societies are contrasted with the less-developed ones, liberal democratic societies with autocratic ones, unitary national states with multi-national empires where the forces of nationality were potent forces of change. The book also analyzes the extent to which modernism and the main features of popular culture already existed before 1914, and how far the social changes characteristic of the 20th century were already discernable.