General Hood’s Road to Golgotha : The last doomed offensive mounted by the South : SHROUDS OF GLORY: From Atlanta to Nashville: The Last Great Campaign of the Civil War, <i> By Winston Groom (Grove/Atlantic: $23; 308 pp.)</i>

You’ve got to hand it to Winston Groom for staying the course after the boggling commercial success of his novel, “Forrest Gump.” The story has been well-documented of how the Alabama author dashed off that whimsical “entertainment” in a couple of months in the mid-80s, and soon began weighing offers from Hollywood that would ultimately lead to “Gump” becoming one of the hottest movies of all time. Rather than dwelling on these prospects, however, Groom calmly chose to pursue an interest in the Civil War that had been festering since his discovery 25 years ago that a great-grandfather had been a private in the cavalry of the Confederate Army.

That ancestor, one Fremont Sterling Thrower, had fought under General John Bell Hood in the failed campaign to save Atlanta. Reading from the documents he found in a metal strongbox in his parents’ attic, Groom found that his great-grandfather’s regiment was then assigned to “follow and harass” Union General William Tecumseh Sherman on his scorched-earth march to the sea. Thrower was wounded in the leg at Savannah, rode out the war, and became a judge in Mobile, who had walked with a cane until his death, in 1925, at the age of 80. There was nothing especially spellbinding in his great-grandfather’s tale, alas, but in the course of his research Groom came upon a story that seemed to capsulize the futile gallantry of the Confederacy before it went up in flames.

“Shrouds of Glory” is a nonfiction account of what turned out to be the last major offensive mounted by the South, an attempt by Gen. Hood’s Army of the Tennessee to head northwest out of Atlanta and regain Nashville through the back door even as Sherman marched southeastward through Georgia. Although the fall of Atlanta had been demoralizing, the South wasn’t out of it yet. The people of the North were weary of the war, demanding an end to it, and it was quite possible that England and France, eager for the South’s diminishing cotton supply, would finally come to the aid of the Confederates if they could pull off this stunning reversal. Thus we are presented one of the more underappreciated campaigns of the entire Civil War.

Primarily a novelist, Groom consulted an astonishing mountain of material--76 published books, more than 100,000 pages of battle reports, hundreds of unpublished personal accounts stored in state archives--to breathe life into a recreation of events some 130 years ago. By the time we enter the story, more than 500,000 lives have been lost on both sides and the Confederacy is in a desperate state. Its last hopes have been placed in the hands of John Bell Hood, a hulking 33-year-old Kentuckian who had graduated 44th in a class of 52 at West Point and now, as head of the 20,000-man Army of the Tennessee, gamely carries on; he had lost a leg at Chickamauga, had an arm mangled at Gettysburg, and is involved in a love affair with a Charleston beauty that ultimately will end in failure. Indeed, failure is the undercurrent throughout “Shrouds of Glory,” for not once does Hood win a battle in the town-to-town skirmishes against a Union army of like size.

The centerpiece of the book is the battle for Franklin, a town some 20 miles south of Nashville, and Groom’s painstaking reconstruction of the events on the last day of November, 1864, shows us the Civil War in all its savagery. All is silent on an Indian summer afternoon as the two armies stare at each other across a swooping two-mile valley--the Northerners safely dug in behind breastworks on one hillside, the Southerners itching to charge directly into their lines--the lull before the storm. “As forerunners well in advance,” a Union officer would recall, “could be seen a line of rabbits, bounding along for a few leaps, and then (they) would stop and look back and listen, but scamper off again . . . and quails by the thousands [finally] rose high in the air and whirred off to the gray sunlight. . . .” Then, suddenly, incongruously, as in a movie, the bands struck up--”Dixie” on one side, “Battle Hymn of the Republic” on the other--and all hell broke loose.

“In all its bloody four years,” writes Groom, “the war had rarely--if ever--seen fighting so ferocious on so large a scale in so confined a space. For nearly an hour, thousands of men within an area no larger than a few acres shot, bayoneted, gouged, and bludgeoned one another to death with rifle butts, axes, picks, guns, knives, and shovels.”

In the brutal hand-to-hand fighting, meticulously reconstructed by Groom from hundreds of archival memoirs, we are presented one of the bloodiest scenes to be found in Civil War literature. When the day is done, Hood will have lost about one-third of his army to death or dismemberment, among the dead being no less than five Confederate generals, and with it all hopes that the course of the war could be altered. The floor of the Harpeth River valley is a killing field, where soon “a big autumn moon rose up and loomed low over the Winstead Hills, bathing the Golgothan scene with an eerie silver glow. Men were still firing, but the intensity of the battle began to slacken under its sheer weight. . . . Now between the diminishing cracks of rifle shots, a horrible and uncanny sound rose off the smoky floor of the Harpeth valley--the pathetic pleadings and cries from thousands of mangled men.”