Whatever must be said to get you to heft this daunting debut novel by Honorée Fanonne Jeffers, I’ll say, because “The Love Songs of W.E.B. Du Bois” is the kind of book that comes around only once a decade. Yes, at roughly 800 pages, it is, indeed, a mountain to climb, but the journey is engrossing, and the view from the summit will transform your understanding of America.

A poet whose most recent collection, “The Age of Phillis,” was longlisted for a National Book Award, Jeffers has poured a lifetime of experience and research into this epic about the travails of a Black family. As any honest record of several centuries must, Jeffers’s story traverses a geography of unspeakable horror, but it eventually arrives at a place of hard-won peace.

One of the many marvels of “The Love Songs of W.E.B. Du Bois” is the protean quality of Jeffers’s voice. Sweeping back and forth across the years, her narration shifts nimbly to reflect the tenor of the times — from the shared legends of tribal people to the candid realism of the modern era. At the opening, set deep in the mists of history, we’re met with an incantation:

“We are the earth, the land. The tongue that speaks and trips on the names of the dead as it dares to tell these stories of a woman’s line.”

You don’t read these phrases so much as hear them on the wind: “We sang then and we sing now.”

Jeffers uses that oracular narrator to carry us swiftly through the foundational sins of North America. “The original transgression of this land,” she writes, “was not slavery. It was greed, and it could not be contained.” Though the European immigrants “had been oppressed in their own land by their own king . . . they resurrected this misery and passed it on.” Kidnapped Africans are hauled across the ocean, while the natives who live here are shoved off or murdered.

Black slavery and Indian genocide may be regarded as distinct historical crimes, but Jeffers constructs her story to illustrate the integration of African and Indian pain in America. Almost immediately, the genealogies of her White European, Native American and enslaved African characters begin to mingle in a collage of expediency, love and rape.

If the convoluted racial composition of these characters is a challenge to track, that’s the point: Despite the strict demarcations of color that reside in the White imagination, the society that evolves in these pages is peopled by a spectrum of hues. Some claim their superiority, most suffer and a few pass.

Out of that cloud of repression, deception and certainty, “The Love Songs of W.E.B. Du Bois” begins to coalesce around a farm in Georgia founded in the early 19th century. Here on this stolen and re-stolen ground, Jeffers carefully unfolds a vast catalogue of human misery. If there are any wisps of nostalgia still clinging to antebellum life, any presumptions of honor still adhering to the Old South, they are burned away by the torch of Jeffers’s prose. Aside from the cruel labor of enslavement, “The Love Songs” drills down into slavery’s most egregious perversity: its function as state-sponsored rape and pedophilia.

Samuel Pinchard, the plantation owner, is a literary descendant of Simon Legree, but Jeffers has drawn him in the full height of psychological complexity. He’s an exceptionally patient and clever businessman, a husband of Olympian self-delusion and a Christian of unfathomable depravity. But more importantly, he’s the lodestone around which the entire plantation society revolves. His crafty mind is the razor’s edge that every Black person imprisoned on this farm must walk.

Jeffers gives herself all the room she needs to knit relationships of these enslaved families. And what a heartbreaking cast of people they are. In the hellish conditions of the plantation where paternity is often suspect or denied or impossible to know, where children and spouses are severed from one another, and where bodily integrity can be violated at any time, the Black women develop remarkable qualities of surreptitious wisdom and courage.

But all this — this gripping story about the outrages endured on a pre-Civil War Georgia farm — appears only in the intercalary chapters, or “Songs,” as Jeffers calls them. In the novel’s longer, modern-day sections, we follow the life of Ailey Garfield, a strong-willed child born in the 1970s. The daughter and granddaughter of doctors, Ailey is a part of what W.E.B. Du Bois once called the “talented tenth,” those exceptional, well-educated Black Americans who will “guide the Mass away from the contamination and death of the Worst.”

Here, again, Jeffers explodes all rigid categories. In her patient examination of life during and after the Civil Rights movement, she traces the persistent, pernicious effects of colorism, the fickle rewards of passing and the crippling burden of being “exceptional.” But Jeffers confers no automatic heroism or martyrdom on her Black characters. Despite all the relative advantages that Ailey and her family enjoy, they can’t escape the long claws of sexual abuse or the ravages of drug addiction — what Du Bois called “a plexus of social problems.” And every move they make must be calibrated against the conflicting demands of their ancestors, their extended family and a White society quick to judge.

Jeffers is particularly deft in the way she portrays Ailey coming of age in the 1980s and ’90s, trying to chart her own way amid heavy guidance from her accomplished family. As a teenager and then a college student, Ailey discovers that rapidly changing attitudes about sexual behavior and the possibilities for women are still tangled up with 19th-century expectations of female purity and masculine power. The college dating scene that Jeffers describes is a treacherous realm in which young women must manage their reputations with exquisite care while young men vacillate erratically between genteel chivalry and sexual predation.

In one of the novel’s many fascinating maneuvers, this story partially set in the past eventually becomes a story about the reclamation of that past. Inspired by the academic achievements of her renowned Uncle Root, Ailey decides to study history, an endeavor that Jeffers dramatizes with tremendous passion. Hers is not just the granular detective work of tracking down documents and interpreting traces of information — although there’s plenty of that. To be a successful Black historian is to endure, with unruffled equilibrium, a barrage of condescension, dismissal and obfuscation from White peers. And what’s more, Ailey’s studies draw her into the grueling emotional labor of confronting the torture her own ancestors suffered: It’s scholarship understood by the mind but felt in the body.

The ultimate demonstration of Jeffers’s skill is that she effects that same profound impression on her readers. With the depth of its intelligence and the breadth of its vision, “The Love Songs of W.E.B. Du Bois” is simply magnificent.

Ron Charles writes about books for The Washington Post and hosts TotallyHipVideoBookReview.com.

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The Love Songs of W.E.B. Du Bois

By Honorée Fanonne Jeffers

Harper. 797 pp. $28.99