The First World War is usually explained by asking what people wanted. Historians have spent a century sorting the guilty from the merely reckless, and the argument has produced magnificent scholarship without producing agreement. This book asks a different question. Not what the men of 1914 wanted, but how long they had.

Every government runs on two clocks. One measures how long it takes to turn information into a decision that carries authority: to decipher the telegram, to find the minister, to convene the council, to obtain the signature. The other measures how long remains before somebody else does something that cannot be undone. The difference between them is a reserve, and when that reserve runs out, nobody decides anything. Everyone simply executes the plan they prepared earlier, and the plans, having been written separately, produce together a result that appears in none of them.

In the last week of July 1914, that reserve went negative across an entire continent. The Kaiser's considered judgment that there was no longer any reason for war reached Vienna after Vienna had declared it. Ultimatums that had begun by granting forty-eight hours were granting twelve. Nobody was asleep. Everybody was late.

The story does not end in 1918. Missile warning gives a president minutes. Cyber attribution takes weeks while retaliation takes hours. Trading algorithms act faster than any meeting can be convened. And the newest machines now compress the time needed to produce an answer without touching the time needed to authorize one, which makes the reserve look healthy at the precise moment it disappears. The financial markets, alone among these domains, have already installed the obvious remedy: a mandatory pause. Everyone else has decided that pauses are for other people.