“Fierce Patriot: The Tangled Lives of William Tecumseh Sherman” by Robert L. O’Connell. Random House, 2014. $28.

There are signs of the Civil War all over LSU. Mentions of the Ole War Skule, the antebellum forebear of the current university, and memorials large — Kirby Smith Hall — and small, like the low plaque in front of the Campanile that mentions the first president of the War Skule in question.

That would be William Tecumseh Sherman. The Union general of the razed earth March to the Sea that burned Atlanta and irrevocably broke the Confederacy. That Sherman.

For generations of students, the toasted condition of Atlanta may be the only fact they can dredge up about Cump Sherman. LSU students may know he was once president, or they may remember the occasional controversy that arises when it comes time to name something on campus and it’s not labeled Sherman.

Robert L. O’Connell’s book changes that. He sets Sherman — and his presidency at the Louisiana State Seminary of Learning and Military Academy — perfectly into the context of his time. Sherman, as O’Connell richly shows, is more than the ashes of Atlanta.

This is not a chronology. It doesn’t begin with his birth and march, as relentless as the Army of the West, on to Sherman’s death in 1891. Instead, O’Connell breaks out pieces of Sherman’s personality and dives in, covering the chronology along the way, where it fits.

By agreeing to head up the Ole War Skule, Sherman plops himself down right on top of the Southern powder keg by now heated by a low, steady boil of secession. A disastrous move from the man who would become one of the U.S. Army’s best strategists. By taking a comprehensive look at Sherman’s state of mind, O’Connell shows how this life-shaping blunder occurred.

“His personal ambition compounded by his relationship with his tightly wired family must have infused him with plenty of emotional incentive to seize this opportunity to establish a military academy — his own little West Point — and ignore the implications in light of the looming crises with the South,” O’Connell writes.

“It might also be said that Sherman had an extraordinarily rigid and exclusive cognitive framework. ... Meanwhile, the whole thing was veiled in a way that let in light only from certain angles, ones that illuminated the structure and preserved cognitive consistency; the rest was filtered out.”

Lincoln’s election and the subsequent secession of Southern states would happen while Sherman sat in the big chair at LSU. O’Connell shows how Sherman honed his leadership skills at the Ole War Skule and how the betrayal of Louisiana’s entry into the Confederacy — and of the institution built on his hard work — hardened him into the Union general he became.

This book is a bold approach to a biography that’s hugely informative and immensely readable. O’Connell’s “Fierce Patriot” may be as close to having a conversation with Sherman as we’re likely to get.