Wanderlust is as American as revival meetings. So, too, is the outlaw instinct. Behind every Butch Cassidy hightailing it over the mountains, there's a posse of dreamers cheering his getaway.

These are Alec Soth's people -- the ragtag individualists, outsiders, scofflaws and loners who populate the national imagination and linger in the mildewed shadows of small-town dives and backwater shacks. In the past decade the Twin Cities photographer has rocketed to international acclaim with his memorably stark portraits of these thoroughly American types.

Riding a wave of acclaim following his national debut at the 2004 Whitney Biennial, Soth has had major shows in Milan, Paris, Seoul, Zurich, London, Bonn and galleries and museums throughout the United States. The latest is a 20-year survey opening Sunday at Walker Art Center.

Subtitled "Alec Soth's America," the show samples his most famous series, "Sleeping by the Mississippi" and "Niagara," dips into his Minnesota work from the 1990s, and includes revelatory new images and publications that introduce a more troubling and complex vision. His work has always been driven by an autobiographical impulse, but the loneliness of life on the road and his fascination with men on the fringe has infused raw edginess into the new work. Even Minnesotans who know Soth's work well from his many previous shows at local galleries and the Minneapolis Institute of Arts will find surprises.

While the show covers a lot of territory, he insists it's not a retrospective. "I'm too young for that," he laughed wryly during a recent preview.

Instead he describes it as "my midlife crisis show," an excursion into byways of the American experience that are farther out of the mainstream and yet perhaps closer to some of Soth's own demons.

"I don't want to say that America is a terribly dark place, but post-9/11 America is a different place, and there's something darker and more sinister that a lot of us have felt," he said. "People have felt this desire to run away forever, but post-9/11 and [Hurricane] Katrina, there is an enhanced desire. Maybe these wackos are on to something."

From Mississippi to Niagara

With his tousled brown hair, jeans and rumpled plaid shirt, the 40-year-old photographer could pass for a footloose laborer or college student. In fact he's a heavily scheduled husband and father of two whose photo business, blog and publishing ventures have him jetting about the world for his own projects and on assignment for Magnum, the Paris-based photojournalism cooperative.

A French film about his work will be screened Sunday at the Walker; a German publisher will release his sixth book in the spring. And next month he and the family will be in England for the opening of a collaborative show of photos by Carmen, his 7-year-old daughter, that he edited for the Brighton Photo Biennial.

The pictures Soth made along the Mississippi River in the late 1990s are the touchstone of his career, huge color portraits of revivalists, small-town prostitutes, empty beds, shabby rooms and lonely prisoners. As the signature image of the Whitney Biennial, "Charles," a flight-suited recluse holding model planes outside his shabby cabin, became an international sensation. Appearing three years after 9/11 shattered America's confidence in its exceptionalism and security, the "Mississippi" series resonated as a portrait of a free-spirited but desolate heartland.

His "Niagara" pictures of 2006 were bleaker, a world of mismatched lovers seeking happiness in tacky motels at the edge of a scenic wonder.

"Everything about the Mississippi project was so easy," Soth recalled recently. "The South was all hospitality. It was a magic trip where everything worked. 'Niagara' was the opposite. People in that part of the country are suspicious. Niagara is not a happy place. The American side is economically devastated and the Canadian side is schlocky and touristic. I did it after 'Mississippi' because it functions in the same way; it's an iconic body of water associated with love and romance. I love the work, but it's dark. I didn't have a love affair with Niagara."

Overcoming foibles

With his ready smile and easy manner, Soth has a naturally winning personality. But he is shy by temperament and had to force himself to approach strangers and ask to take their photos. Rarely shown silver prints from the early 1990s document his efforts to overcome inhibitions and demonstrate his debt to such masters of black-and-white photography as Robert Frank, Henri Cartier Bresson, Robert Doisneau and others who specialized in candid street shots. Made in places of casual encounter, they have themes like "Perfect Strangers" (dancers at singles events), "Powderhorn Park," (picnickers), "At the Bar," (drinkers and talkers), "Nordeast" (working stiffs).

His eye for incongruities turned up "Cop and Clown," a charming portrait of a uniformed policeman and a top-hatted clown sitting at adjacent tables in a St. Paul skyway cafe. "That won a blue ribbon at the State Fair back when the ribbons were small," he chuckled proudly. (Soth always submits a photo to the fair.)

He made his reputation with color prints taken with huge old-fashioned cameras that produced 8-by-10-inch negatives he generally processed himself. Trained in traditional darkroom techniques, he couldn't afford to work in color until he won a McKnight Photography fellowship in 1999. The digital revolution has forced more changes. Until last year he shot everything on film, but he now shoots primarily with a digitized Hasselblad camera, which produces square images, or a high-resolution digital camera in a 35-millimeter-style format.

Books are another key to his success. He typically edits major projects into free-association visual narratives that build an emotional and psychological mood. The German publisher Steidl has issued his major projects, and he releases zines under his own imprint, Little Brown Mushroom. The Walker show has shots from "Fashion Magazine," a sly 2007 sendup of the fashion business, and his recent portraits of goth women and lonely guys in Missouri. Portraits of Kmart shoppers, an ice skater and a terrier belonging to Twin Cities art collector Dar Reedy hint at Soth's playful side.

Hiding in plain sight

Even the walls are gloomy in the show's final gallery, a cavelike space that cocoons dozens of images of survivalists, recluses, outsiders and their environs under the title "Broken Manual." Among them is a small black-and-white photo of a burned-out bus at the Branch Davidian compound in Texas and a large one of the forested view from the Unabomber's cabin. Color portraits include a bearded redhead dozing in a mossy glade, a wary young man with a swastika tattoo in an Edenic landscape and "The Arkansas Cajun's Backup Bunker" showing a man and his container-shelter. All are men he found through the Internet or by rambling down a road or because "people talk."

"'Broken Manual' is a play on words," he said. "These are all broken men. You can't run away from your life or retreat, because we all need people and society, but this is my midlife crisis project. I'm happily married with two kids, but I have this fantasy of chucking it all and running away."

"There is a sadness to this work," he said later. "There is this element of a certain kind of male longing. Longing for what? For independence, self-reliance, all those things that are part of the American identity."

There's also an exquisitely modeled 4-foot-tall maquette of a tree house beneath whose mossy roots is a cave heaped with books. Its secretive landscape calls to mind Marcel Duchamp's famous last work, a cavelike 3-D vignette visible only through a peephole. Nearby is a display of "Broken Manual" books containing a tract supposedly written by Lester B. Morrison, who also is credited with creating the maquette.

The mysterious Morrison -- whose photos are now in a show at the Soap Factory in Minneapolis -- also has 'zines available via Soth's blog, and contributed a poem to Soth's 2008 project, "Last Days of W."

Morrison appears to be a thinly veiled fictional alter ego for Soth, whose Little Brown Mushroom blog shares Morrison's initials. The artist even admits that he "actively was trying to buy a cave for the past year and a half." Still, "I don't want to ruin the mystique," he said, insisting that Morrison is "just a guy I met."

As he's photographing, Soth often asks his subjects about their dream in life. Asked about his own, he paused a long time and chuckled nervously.

"Ahh. I have to think about that one," he said. "The problem is that I want two things simultaneously and they're contradictory. I want solitude, independence and all that, and to be loved and adored and coddled on the other side. Lester doesn't like that part of me that wants to be loved and coddled."

mabbe@startribune.com • 612-673-4431