On a calm, cool evening in early June 1917, British Major General Charles Harington gathered with a group of reporters on the Western Front to discuss a massive attack that would be launched soon against German forces. Rumors had been drifting for weeks of a major offensive planned near the Belgian town of Messines, and the reporters were eager for details.

By that point, three years into Europe’s ghastliest conflict, neither the British nor their allies had made much progress against the enemy. The Germans, likewise, had failed to land a decisive blow. Armies on both sides were drained, demoralized, and slowly growing weaker along the blackened ribbon of frontline that stretched from the North Sea to Switzerland. The reporters huddled