So today it all began, the war that took 8.5 million lives, and wounded 21.2 million more, that began the war that begat the bomb that ….

There are all sorts of books about the beginnings [see below], but here is a summary I think will serve, from T.G. Ott in his July Crisis, 2014, a meticulous, hour by hour accounting of what was going on in the high scaffolding of Berlin, Vienna, St Petersburg, Paris and London throughout the month of July, 1914

…the Great Powers had not somehow ‘slithered over the brink’ as Lloyd George [Chancellor of the Exchequer and then Minister of Munitions] put it so evocatively in his war memoirs.  War had come as a result of individual decisions and a rapid series of moves and counter-moves by the chancellors of Europe, and set against the backdrop of recent shifts in the international landscape and anticipated further changes in the years to come.  The Powers did not operate in a vacuum.  If, in 1914, there was no formal and largely institutionalized framework of international politics of the kind that exists today at different level, there as nevertheless a system of Great Power politics– the European concert, with its norms of behavior, accepted rules of conduct, and conflict-solution mechanisms..

Abstract concepts, such as ‘balance of power’ or the ‘alliance system’ did not cause Europe’s descent into war.  Nor did states in the abstract propel the Powers along the path towards war.   As this reexamination of the decision-making process has shown, individuals acting in response to external and internal stimuli, and to perceived opportunities and threats, were central to developments in July 1914  Their hawkish or dovish views on the perceived realities of international politics, and how they maneuvered in the space given to them within the existing political arrangement in their respective countries, hold the key to understanding how and why Europe descended into world war.

For a good survey of recent histories about the beginnings of the war see this by Gary Sheffield from the University of Wolverhampton