No era in the history of the United States has been so scrutinized as the four years when brother fought brother over the issues of self-government and slavery. So it's fair to ask whether journalist S.C. Gwynne's new book, "Hymns of the Republic: The Story of the Final Year of the American Civil War," is really necessary.

My answer is yes. Too many Civil War books drill so deeply into the conflict that one can lose sight of what it all means. That's not the case with Gwynne's lucid and gripping account, in which he strings together a series of vignettes and profiles of wartime figures in novelistic fashion to tell the story of the war's tumultuous closing months, through Abraham Lincoln's assassination and Jefferson Davis' humiliating capture in Georgia.

Gwynne won his Civil War spurs for his acclaimed 2015 biography of Confederate Gen. Stonewall Jackson, whose brilliant career was cut short by friendly fire in 1863. In this book, the author picks up the narrative a few months later, when Ulysses Grant arrives in Washington without ceremony, looking just like "another sunburned soldier in an army hat and linen duster," to take charge of the snakebit Army of the Potomac.

It was the start of the war's most crucial year, arguably the most dramatic months in the nation's history. From battlefield to ballot box, what happened in 1864 likely would determine whether there would continue to be a single United States or two countries sharing a border.

The outcome was by no means certain. If Grant's army proved unable to roll back the vaunted forces of Gen. Robert E. Lee, prospects were grim for Lincoln's re-election. And if voters rejected Lincoln, chances were good that the next president would let the South go in peace.

As related by Gwynne, the year was punctuated by bloody turning points. In April, Confederate soldiers shot black Union troops rather than allowing them to surrender at Fort Pillow, Tenn., outraging Northerners and strengthening their resolve. The following month, after a series of Union disasters in the tangled Virginia woods, Grant continued to move south rather than retreat. Union soldiers were dumbfounded — and grateful. They were finally going to press the rebels.

S.C. Gwynne

William Tecumseh Sherman's capture of Atlanta overnight bolstered Lincoln's re-election prospects, reversed Northern pessimism about the war and ensured it almost certainly would end in a Union triumph. By the time the Confederate government reluctantly called for the enlistment of 300,000 black soldiers, granting them freedom in exchange for service, Gwynne writes that "a moral threshold had been crossed. Slavery as an institution was as good as gone."

Gwynne is especially good at taking a step back from the narrative to flesh out some of the war's most compelling figures, and not just Lee and Grant. He sketches officers of varying competence, such as Union Gen. Ben Butler, who was better at preparing for attacks than making them, and Confederate guerrilla leader John Singleton Mosby, whose late-night raids of supply trains drove a frustrated Grant to order (briefly) the arrest of local civilians.

The profiles that stand out most are those of the indomitable Clara Barton, who wasn't allowed to fight and thereupon mounted her own relief agency to tend to those who could; and Sherman, the cross-grained Union general who figured the most merciful thing he could do for both sides was to hurt the South as much as possible.

Gwynne, a former correspondent for Time and executive editor of Texas Monthly, volunteered during a recent panel discussion in Austin that his next book will be on Reconstruction and titled "How the South Won the Civil War." Another Civil War book? If it lives up to the promise of the first two that Gwynne has written, why not?

Kevin Duchschere is an editor at the Star Tribune. • 612-673-4455

Hymns of the Republic: The Story of the Final Year of the American Civil War
By: S.C. Gwynne.
Publisher: Scribner, 395 pages, $32.