Two college friends’ leisurely river trek becomes an ordeal of fire and human malice in Peter Heller’s “The River.”

For his fourth novel, Heller swaps the post-apocalyptic setting of his previous book, “The Dog Stars,” for present-day realism — in this case a river in northern Canada where Dartmouth classmates Jack and Wynn have cleared a few weeks for fly-fishing and whitewater canoeing. Jack is the sharp-elbowed scion of a Colorado ranch family, while Wynn is a more easygoing Vermonter — a divide that becomes more stark as the novel progresses — but they share a love of books and the outdoors. They’re so in sync early on that they agree to lose travel time to turn back and warn a couple they’d overheard arguing that a forest fire is fast approaching. It’s a fateful decision: They discover the woman, Maia, near death and badly injured, apparently by her homicidal husband, Pierre. When Wynn unthinkingly radios Pierre that she’s been found alive, Wynn and Jack realize they’re now targets as well. Heller confidently manages a host of tensions — Jack and Wynn becoming suspicious of each other while watching for Pierre, straining to keep Maia alive, and paddling upriver to reach civilization and escape the nearing blaze. And his pacing is masterful as well, briskly but calmly capturing the scenery in slower moments, then running full-throttle and shifting to barreling prose when danger is imminent. (The fire sounds like “turbines and the sudden shear of a strafing plane, a thousand thumping hooves in cavalcade, the clamor and thud of shields clashing, the swelling applause of multitudes. …”) And though the tale is a familiar one of fending off the deadliness of the wilderness and one's fellow man, Heller has such a solid grasp of nature (both human and the outdoors) that the storytelling feels fresh and affecting. In bringing his characters to the brink of death (and past it), Heller speaks soberly to the random perils of everyday living.

“The River” is an exhilarating tale delivered with the pace of a thriller and the wisdom of a grizzled nature guide.

(Heller will speak and sign copies of his book at 7 p.m. Wednesday at Austin Central Library, 710 W. Cesar Chavez St. Information: bookpeople.com)

Essays from the personal to the political

A novelist and essayist with a peripatetic life, Xu Xi returns with “This Fish Is Fowl,” a collection of recent and revealing pieces that range from the intensely personal to the analytical to the appreciative.

Xu Xi, who writes in English, has published a number of novels (“That Man in Our Lives”) and a memoir (“Dear Hong Kong”). Here, she collects 30 tight essays — many previously published — and arranges them, sometimes chronologically, in four categories. Among the most wrenching are those dealing with her mother’s long descent into Alzheimer’s and the author’s care for her (“the typhoon that was my mother’s Alzheimer’s changed my world, shifting all its known compass points”). The author is also candid about her two divorces, her current and long-lasting relationship with another man, and her brother’s death. She also writes affectingly about writing itself: why she writes in English (she says her Chinese is not all that good) and how she, in some ways, disappointed her mother, who did not eagerly approve of her daughter’s decision to become a writer. The author also chronicles a long process of decision about what she should do besides write — something that would earn her a steady, predictable income. She was in the corporate world for a number of years and then moved into academe, where she now works as the co-director of the MFA program in creative writing and literary translation at the Vermont College of Fine Arts. In one essay, the author discusses how she likes to “loaf,” but these essays reveal a writer who is intensely focused on her work. There are a few political pieces, as well, including one that features, woven throughout, letters to Hillary Clinton, whom the author supported during the 2016 election. (She zings the winner of that election a few times, too.)

These broad-ranging, introspective and honest essays reveal a fine writer’s experiences, mind and heart.