Crossing the Canadian border, Angela Palm, a married mother without a set career, surprised herself by responding "I'm a writer" when Border Patrol asked her occupation. Recognizing the insecurity in her voice, the officer asked her what it was that she wrote. "Look at me when you say it," the officer added.

"I was glad she said that," Palm recounts. "To look at her, I mean. Disallowing anything but facts. Demanding an unflinching reply." This was a wakeup call. "Writing is seeing. There is an obligation to complete the half-written letters, assemble the tales, stitch together the truths. Of that, I am certain."

Palm's memoir, "Riverine," is the winner of this year's Graywolf Nonfiction Prize. Previous winners include Leslie Jamison for "The Empathy Exams," and Eula Biss ("On Immunity") for "Notes From No Man's Land." Like past winners, "Riverine" is an incredibly personal and eloquent book. Circling buried truths and confronting ghosts, this is a book that wrestles with issues of nature and nurture.

Growing up along the Kankakee River, Palm lived with proud but poor parents in an area that was created by redirecting the river. Periodic flooding made an island of her home. Describing the communities that occupied this land, Palm confronts questions such as whether or not geography determines fate. If we can reroute a river, can we ever escape the isolation of poverty? How can we transcend our surroundings?

These questions echo in the pacing of Palm's life as she seeks refuge in religion, art and late-night bartending. This search sends her from Indiana to Vermont, hoping to find solace in a new landscape of green mountains. Yet at each bend, she finds herself back where she started from: aching with unrequited love for the boy next door.

Corey was not just any boy next door. As children who grew into curious teenagers, their bedroom windows looked out onto one another. This connection bound them together even after Corey was found guilty of a double homicide.

"Riverine," by Angela Palm

Their devotion muddles all that Palm knows to be true. Despite that, Corey is her true north, the steadfast prism through which she regards both the beauty and injustice of the world. Riddling the opposite endpoints of their entwined lives, she recognizes the power of nostalgia and memory, wrestling with its hold over her present life. Palm's memoir is lifeline and letter to the parallel universes we so often wish for. Hers is a raw but wistful voice that embraces the imperfection of language as a reflection of the impossible question of what it means to be true to one's self.

Lauren LeBlanc is a freelance book editor and writer, as well as a senior nonfiction editor at Guernica magazine. A native New Orleanian, she lives in Brooklyn.

Riverine
By: Angela Palm.
Publisher: Graywolf Press, 253 pages, $16.