The Sleepwalkers: How Europe Went to War in 1914

Clark starts from a simple shift. Instead of asking who started World War I, he asks how an assassination in a Balkan city turned, in little more than a month, into a war that involved almost all of Europe. The question of who pushes the reader to look for a single culprit; the question of how forces you to look at the whole process, with dozens of small decisions adding up.

This choice is not neutral. For decades, much of the historical scholarship treated Germany as the main party responsible for the war, following the line of the historian Fritz Fischer. Clark does not deny that Germany acted irresponsibly, but he argues that putting the main weight on a single country hides how much other powers also pushed the crisis forward.

The result is a book about group decision-making under pressure, not about villains. Think of a family argument that escalates because nobody wants to be the first to back down: each side feels defensive, every gesture is read as a threat, and nobody in the middle of it has the full picture of how it will end.

Before July 1914, Europe was already split into two alliance blocs. On one side, the Triple Alliance, joining Germany, Austria-Hungary, and Italy. On the other, the Triple Entente, made up of France, Russia, and Britain. Each alliance was born as a security guarantee, but the side effect was to turn any regional quarrel into a risk of dragging in the entire continent.

It's like a neighborhood group in which every family promised to back up the next-door neighbor in case of trouble. The intention was mutual protection, but in practice any small disagreement between two houses risks pulling everyone into the fight, because nobody wants to look like they abandoned the people they promised to help.

Clark shows how this alliance system created a perverse incentive: each country feared looking weak in front of its allies, and so hesitated to back down publicly in a crisis, even when backing down would have been the most sensible decision for its own good.

Serbia at the start of the 20th century had just doubled in size after the Balkan Wars and was going through a moment of strong national pride. The country saw itself as the natural core of a future, larger Slavic state, bringing together territories that were still under Austro-Hungarian rule.

This project had a name: irredentism, the idea of reclaiming lands inhabited by people of the same nationality, even if they officially belonged to another country. From Vienna's point of view, Serbia was a direct threat to the integrity of the Austro-Hungarian Empire, which had annexed Bosnia in 1908 and saw its own internal Slavic population as a powder keg about to blow.

Russia, for its part, saw itself as the natural protector of the Slavic and Orthodox peoples of the Balkans, driven by a sentiment called pan-Slavism. Any threat to Serbia sounded, in Saint Petersburg, like a threat to a distant relative who needed help.