Amos Humiston was one of the more than 23,000 Union casualties of the three days of fighting at Gettysburg. Mortally wounded, he managed to pull from his uniform coat an ambrotype of his three children -- Frederick, 4; Alice, 6, and Franklin, 8 -- on whom he presumably gazed as death took him. His body was found at the end of the battle with the image pressed to his heart.

Humiston was far from the only man to die in the Civil War clutching a photograph. In "This Republic of Suffering," author Drew Gilpin Faust quotes from a letter by Confederate soldier William Stilwell to his wife, Molly, in Georgia: "I have often thought if I have to die on the battlefield, if some kind friend would just lay my Bible under my head and your likeness on my breast with the golden curls of hair in it, that it would be enough."

The meaning of the war to Americans of that age -- and, indeed, to Americans of every generation since -- has been linked irrevocably to its cost. "The nation's value and importance were both derived from and proved by the human price paid for its survival," Faust says. And that cost was staggering: More than 620,000 dead and hundreds of thousands wounded and disfigured.

More than 2 percent of the 1860 population of the United States perished in that war. An equivalent toll in 2008 would be 6 million.

How Civil War-era Americans coped with this unimaginable calamity is the core of Faust's extraordinary book. She expertly explains the ways in which Americans North and South -- deeply religious and anchored by custom and geography to home and kin -- struggled with death on so vast a scale and often so very far away.

Using personal letters, official documents, reminiscences and newspaper accounts, she describes the efforts to retrieve the dead from makeshift graves, identify them and return them to their families. That effort gave rise to the first government graves registration procedures and, later, the development of an embryonic national cemetery system.

Southerners were excluded -- prompting one Richmond newspaper to comment bitterly on the irony of keeping Southerners outside a nation with which they had been forcibly reunited -- but the private efforts of Southern women were amazingly effective in creating resting places for the Confederate dead.

Faust recently was elected president of Harvard University, where she holds the Lincoln Professorship in History. Her previous books -- "Mothers of Invention: Women of the Slaveholding South in the American Civil War" and "Creation of Confederate Nationalism: Ideology and Identity in the Civil War" -- rank her among the most thoughtful, influential and important American historians.

In "This Republic of Suffering," she not only has illuminated a neglected aspect of the great conflict with signature erudition, insight and grace, but in the process she has put to rest Walt Whitman's famous lament that the "real war will never get in the books."

Michael J. Bonafield is a Star Tribune copy editor and staff writer.