I was looking forward to seeing Tony Horwitz again last Tuesday, when the author was on the Politics and Prose bookstore docket to speak about his magisterial new work, Spying on the South. The volume was inspired by a kindred spirit, Frederick Law Olmsted, a founder of The Nation in 1865.

Washington was Horwitz’s hometown, so Tuesday was marked on many calendars. He grew up in Chevy Chase, Maryland, a posh enclave on the District line. In a storied life cut short, Horwitz died of cardiac arrest on Monday, Memorial Day. He collapsed on a walk near his brother’s house here. He was 60, seven books to his name.

A Connecticut Yankee, Olmsted was the only journalist in the 1850s to travel to the other side of the sectional divide as the nation neared the Civil War. Observing the cruel face of slavery with a gimlet eye, he published dispatches in The New York Times.

Horwitz’s oeuvre reveals a frank fascination with that divide, as it existed then and in its persistence now in the Trumpian age. His ode to Olmsted, the tale’s fellow traveler, could not be more timely. Tony journeys by train, river steamboat, and donkey across the same terrain, from the Cumberland in Maryland (a slave state) to Tennessee and farther into the Deep South, Texas, and the simmering Mexican border. Horwitz heard “antebellum echoes” everywhere.

Speaking for me, weary Washingtonians needed a tonic of the author’s subversive sparkle. Horowitz had given a great talk on his John Brown book, Midnight Rising, after its 2011 publication. And I remembered Tony from younger days.

Horwitz and his wife, author Geraldine Brooks, lived on Martha’s Vineyard, in the heart of the island. Their sons, Nathaniel and Bizu, had blossomed into young men. I knew the couple when we started a small book club of six. Tony suggested the name, “Jews with Views” (five of six, anyway).

All his books were born of adventure. In the early Baghdad Without a Map, Horwitz all but declared to the literati that he wasn’t afraid to venture into the unknown, getting wet and dirty or hot and dusty. Authentic engagement with his subjects (living or dead) demanded he live hard to tell the narrative. Blue Latitudes, a recreation of Captain Cook’s voyage, extended that vision to the high seas.

Horwitz was not a credentialed historian, which may account for his fresh takes and original voice. Columbia Journalism School trained him well to become a war correspondent and a Pulitzer Prize winner in 1995 for a muckraking newspaper story on poultry factories down South. When he crossed the bridge to books, he knew well how to ask questions, take notes on quotes, probe, and write conversationally. He made rigorous history beguile and belong to everybody, in a jazzy way.

Confederates in the Attic (1998) was a best seller on the Civil War battle reenactment craze. Tony hit the water right, translating the cosmic meaning of weekend affairs reenacting Antietam, Gettysburg, and other battles. He embedded as a Confederate, butternut-gray uniform and all, chronicling forays. Assigned to cover a couple as a Baltimore Sun reporter, I saw such spectacles as inappropriately equalizing both sides of contested ground. Call me a damn Yankee.

Tony and Geraldine threw an outdoor dance party to celebrate the book. I met a leading character. “Important as all get-out” was how he described living like yesteryear’s soldiers. Tony wrote lightheartedly about ersatz Confederates. This was another country in the late 1990s, under the sun and stars.

Awakening New York, Boston, and Philadelphia society, Olmsted broke myths of the antebellum South, chiefly how contented enslaved people were on plantations. He witnessed whippings. His unflinching collection, The Cotton Kingdom, is the best record of how the other half lived, in black and white. (Charles Dickens also left a vivid portrait of slavery in 1842, American Notes.)

The Mason-Dixon Line sharply separated worlds of difference. Few could cross over. Olmsted, in his 30s, had outsize talents, but he had not yet become the founding genius of American landscape architecture. Horwitz confessed he was “hooked” on the inventive Olmsted. I know what he meant. “Fred” makes first-class company, a major figure in shaping the nation.

Perhaps only Horwitz could capture and match his spark, step for step. Spying is a deeper, darker dive into the South, many scenes missing the charm. Starkest was Angola, the harsh Louisiana prison—once a plantation—where inmates raise cotton and other crops. “Lifers without parole had even less chance than slaves of ever being free,” Horwitz wrote.

In a Texas town, Crockett, Horwitz heard ugly racist talk in a crowded restaurant. Upon leaving, he felt melancholy, “as Olmsted had after his testy encounter with slave masters in Nashville.”

Yet the story of the national divide beats on. It’s just taken turns down the river into the past. Horwitz’s masterpiece reads like an elegy.