"Ruin” is the title of the prologue to this memoir by wilderness activist Amy Irvine, and indeed, ruins—both material and metaphorical —stretch over the pages of her book. The ruins of a red-rock desert landscape being logged, mined, drilled and overspent; the remains of her failed first marriage and the precarious passions of a second; the wreck of her father’s life, which ended in suicide; the remnants of a childhood Mormon faith; and the relics of ancient desert dwellers through which she attempts to read all the other remains. Together they create quite a pile of rubble.

A lesser writer might have been tempted to label and classify, restore and rebuild, perhaps even conclude with a renovated life. Irvine chooses instead to survey the site of her losses and ruminate over what she finds there. “The desert holds the past with the reverence of a pallbearer,” she writes near the beginning of Trespass. “I want to witness the procession.”

The newest member of the school of Western naturalist writers that includes Wallace Stegner, Edward Abbey, Ellen Meloy and Terry Tempest Williams, Irvine deserves the attention that affiliation with such writers offers. Her prose is both gritty and lyrical, and her movement between land, memory, marriage and faith, while at times disorienting, is amazingly seamless. Yet while Irvine’s ecological, historical and emotional sensibilities are well honed and movingly expressed, her religious understandings are a little less mature. The result is a slightly uneven memoir, one that at times captures nuance and at other times misses it—although perhaps, as with desert topography itself, roughness is part of the book’s beauty.

Irvine’s book is structured around the four eras of prehistoric peoples in the American West: the Lithic, Archaic, Basketmaker and Pueblo. She imbricates her own story on their arc of “progress,” asking along the way whether the Anasazi’s move from migratory lives of hunting and gathering to more agricultural and sedentary lifestyles, often considered to be a civilization’s advancement, actually constitutes decline. As people moved from nomadism to agriculture, she says, they concretized gender roles, instituted dogmatic religious ceremony and generally moved from freedom and health toward anxiety and excess. “A spiritual life began to be sought at the expense of a sensual one,” she writes (apparently unaware of her own tendency to fall into dualisms). “Perhaps the greatest loss suffered at the dawn of agriculture, at the beginning of life lived in one locale, was the loss of good sex.”

Similarly, Irvine mourns her own losses—not of sex, but of meaning and community and the desert she loves. She begins the book with her migration away from her first marriage and Salt Lake City to rural San Juan County to mourn her father’s suicide and to live with her lover and soon-to-be husband, an environmental attorney named Herb.

Situated within the borders of Deseret, the promised land to which Brigham Young led the Mormons in 1847, San Juan County becomes a site of trespass for Irvine. For a while she tries to keep secret her grant-writing work with the Southern Utah Wilderness Alliance, since such an affiliation is a scarlet letter among her rancher and Mormon neighbors. Longing for community and relationship, she finds her loneliness distilled one Christmas afternoon when she sees a rancher in a pickup waiting for deer to cross the road. “Standing in the trees, watching him, I ache with envy,” she writes. She imagines him returning to his family to celebrate the holiday and attend church the next day. “And I realize: In order to survive, I must expand my territory. I cannot continue to lurk at the periphery of this desert. I will have to creep in, find openings for some semblance of acceptance.”

Irvine tries to disguise her tree-hugger status for a time, with sparse success, begging Herb not to reveal his line of work at social functions and at one point even donning the modest, simple dress of a conservative LDS member. She eventually gives up trying to fit in and accepts her role as an interloper. She and Herb buy a cabin in a canyon and live off the grid for five years. There, her increasing remove from community and convention, Herb’s workaholism, the creep of mundanity that threatens to replace their earlier passion, an undiagnosed hormone deficiency and a miscarriage all threaten to destabilize her emotionally. She and Herb end up having a baby and moving to a house they build in Colorado, where she tries to find healing after Herb’s infidelity and away from the strictures and suspicions of Deseret.

As a writer, Irvine is at her strongest in her descriptions of red-rock country, its beauty and harshness and fragility and resilience—and its losses in an era of off-road vehicle recreation, golf-course expansion and Americans’ insatiable appetite for oil. She and Herb and other environmentalists engage in several standoffs with local citizens and officials as they try to protect public land for possible wilderness designation by the federal government. When she describes their attempt to keep an off-road-vehicle event from going on some friends’ property, Irvine highlights a difference between the standoffish but polite Mormons and ranchers she grew up with and the more aggressive extreme recreationists who incarnate what a friend calls the “new West.” “I can’t help thinking that they embody what may be the Last Days in Deseret,” writes Irvine, “not in a Christ-returns kind of way, but in terms of what the landscape can withstand.”

It is hard to imagine that Irvine’s emotional explorations, especially of her father’s character and failings, could be any more exquisitely wrought. Her father, who frequently escaped a mind-numbing job and fast-paced urban life to go fishing and hunting, found solace away from religious and social convention in the wilderness and, unfortunately, in alcohol. “I have always lived at the tip of a frail slender branch that threatens to break whenever I am forced into close quarters with others,” writes Irvine. “It was . . . the thing about me that aligned me with my father. It was, above all reasons, why I have always turned tail and run to remote places. Which is why it was only a matter of time before I ducked into a place like San Juan County.”

Irvine is less willing to consider the subtleties of religious faith than the nuances of the wilderness or gradations of human history and emotion. A sixth-generation Utahn with an ancestor who served in Joseph Smith’s inner circle, Irvine seems to feel an insider’s entitlement to paint Mormonism as monolithically patriarchal, uninformed and exclusionary. At one point she draws an extended parallel between Mormons and coyotes.

Irvine’s mother was a “Jack Mormon” (lapsed in the faith), and her father was an atheist. She frequently mentions the salient sense of marginalization that she and her sister experienced growing up in Salt Lake City. Unlike Terry Tempest Williams, who has said in interviews that she finds sustenance for ecological work within her Mormon tradition’s emphasis on community, land and service, Irvine seems either unaware of the growing Mormon conservation movement or unwilling to complicate her more convenient categories of doctrinaire religionists and sensitive environmentalists. Irvine cites Williams’s work and thanks her in the acknowledgments, but nowhere in this book does Irvine make mention of the Mormon land ethic that Williams credits as formative in her own writing and that is revealed in a book she edited, New Genesis: A Mormon Reader on Land and Community. One can’t blame Irvine for her painful past with the Mormon faith, but one can hope that wilderness advocates like her will find allies in unexpected places, perhaps even in the shadow of the angel Moroni.

Readers may wish for a little less ruin and a little more restoration than Irvine offers. She does not end with a call for more progress; after all, she claims, the ancestral Puebloans’ demise lay in a spiritual and ecological crisis brought on by their “advancement.” And while she considers challenging readers to regress in a way—to move toward a hunter-gatherer lifestyle that “might bring us into better harmony with one another, and with the land”—she forgoes that idea when an anthropologist friend laughs and tells her, “Amy, you can’t go back.”

Instead, Irvine concludes with a call to go deeper into the heart of things—the desert, relationships, spirituality—“where a certain neutrality exists. A place that can hold everything, that banishes nothing.” “I still hardly know what will ultimately save my marriage, or the desert wilds,” she writes. “I only know what fails, and that I haven’t given up on either.”