It's always a pleasure to discover another superb writer who had not been on my radar. I now must add Aaron Gwyn to that short list. His third novel, "All God's Children," is a stunner. In this beautifully written historical epic, westward expansion, race relations and the nation's mythical place as "a shining city on a hill" collide in an explosive, lyrical reckoning.

Gwyn's debut book of stories, "Dog on the Cross," set among Oklahoma Pentecostalists, earned kudos from critics and made him a finalist for the New York Public Library's Young Lions Award. But the author himself has dismissed his first novel, "The World Beneath," as unworthy of his talents. With "Wynne's War," vivid with U.S. soldiers bloodied in Iraq and Afghanistan firefights, however, he rebounded in spades.

"All God's Children" follows two intriguing protagonists, Duncan Lammons, a young white sharpshooter seeking adventure, and Cecelia, an enslaved woman without a surname. Their paths eventually cross on the Texas frontier, from 1827 to 1847, while it is transformed from Mexican province to sovereign republic to part of the United States. Gwyn's strategy of telling their stories in alternating chapters, using first-person for his white protagonist and third for his Black, not only heightens the suspense but underscores their disparate worth on the American scale.

Duncan, we soon learn, has fled his native Kentucky out of shame over his attraction to men. "I hated this thing inside me, resenting the hold it had," he says. "How many times had I prayed for God to remove … this tumor."

Cecelia is also not quite what she seems. A house slave in Virginia, she has been taught to read by her mistress and to recite poetry to dinner guests, as a sort of pet. But, acquainted with her Homer, Cecelia realizes that she, too, has the makings of a wily Odysseus. She vows to run away, fails several times, and then is sold into the Deep South, left to toil as a field hand.

Gwyn unites these two via Sam Fisk, a handsome Arkansan who joins a smitten Duncan in military expeditions against Mexicans and Comanches. Later, Sam spends time in Mississippi, where he takes pity on Cecelia on the auction block and brings her back to Texas. She is wary of him, he's not sure what he has in mind, either, and Duncan seethes with jealousy. Theirs is an intriguing triangle that evolves into surprisingly novel arrangements.

Gwyn writes fresh, vigorous sentences, and many scenes pulse with tension, tenderness or both. He's as adept at describing battles as his characters' mercurial changes of mood, wavering between trust and suspicion, fear and anger.

Meanwhile, the country slides inevitably toward civil war. In a coda set in 1861 Kansas, the abolitionist Duncan peers into the future, tugged between horror and hope.

Dan Cryer is author of the biography "Being Alive and Having to Die: The Spiritual Odyssey of Forrest Church" and the memoir "Forgetting My Mother: A Blues From the Heartland."

All God's Children

By: Aaron Gwyn.

Publisher: Europa Editions, 400 pages, $18.