Seventy-one years ago Ernest Hemingway suffered the shock—or rather the two shocks—of his young life. He came to World War I at 18, fresh from a few months as a cub reporter in Kansas City and only a year out of Oak Park high school. His war didn't last long. He served as a Red Cross ambulance driver in Italy for only five weeks before he was badly wounded at Fossalta di Piave near midnight on July 8, 1918.

A great deal has been made of the effect of that wounding. Certainly the Austrian Minnenwerfer which threw the projectile across the river, to explode among the men Hemingway had just brought cigarettes and chocolate to, disabused him of any lingering belief in his own immortality. In Melville's memorable phrase from another war, what like a bullet can undeceive. Except that Hemingway was hit by more than a bullet: at the explosion hundreds of metal fragments ripped into his legs, and he thought he was dying. He tried to breathe and could not. He tried to move and could not. He felt his soul flutter up and away from his body like a weightless handkerchief. He survived that trauma, but did not soon outlive it. Time and again, in his fiction, he revisited the moment of his wounding and its aftermath. For years, he had difficulty sleeping without a light.

When the wounded Hemingway finally reached the Red Cross hospital in Milan, Agnes von Kurowsky was already there. It was she—this tall and vivacious American nurse with the Teutonic name—who was to administer the second wound, a blow that shaped the life and career of Ernest