Evan Tanner figured he could survive the walk back to civilization. Just seven miles, the sign said. Seven miles to the nearest small town, The Dalles, here at the far end of the Oregon Trail.

So he kicked the stand from under his Harley-Davidson and heaved the bike forward. He was one of the fittest men around, a world champion fighter, but he was pushing 700 pounds of motorcycle and gear, and he was exhausted from riding 1,200 miles in three days. But he took one step, then another, bending his mind against the distance and the weight.

His mind had caused this trouble, as he saw it. He had known that little fuel remained in the bike's tank, and there were no gas stations on this remote road near Oregon's Columbia River. A few minutes earlier, riding along, he had mentally shrugged when he saw the sign noting the miles ahead. "Seven miles," he thought. "I could push it seven miles." That's when the bike sputtered to a stop.

He saw meaning in everything, and his bike conking out was no different. "It was a challenge," he would say later. "I had unintentionally thrown it out there at myself." Now, trudging along the road, he considered calling the friends he had been traveling to see. But midnight approached, and he didn't want to inconvenience them.

"It's not going to be so bad," he thought at first. But the road led slightly uphill from the river, and within a few minutes sweat dripped from his forehead. His massive shoulders burned, and his legs shook. Three hundred ninety-nine.... Four hundred.... he thought, measuring his steps between rests. Four hundred steps, rest. Three hundred, rest. Two hundred. One hundred.

Throughout his life Tanner had faced challenges – he called them "adventures," others called them demons – and triumphed in remarkable ways. He lived with extraordinary purpose, rising from the dust of Amarillo, Texas, into the glow of Las Vegas, and along the way he helped build an empire called the Ultimate Fighting Championship (UFC). But he differed from his peers in significant ways; he studied philosophy, for one, and he felt he had a message to share with the world, something bigger than himself, bigger than men fighting for sport.

First, though, he needed to reach the next small town on this misbegotten road. He pushed the Harley for hours, interrupted only by long-haul trucks that blew past in the darkness, missing him by inches. Finally he saw a light ahead: an all-night gas station. He had survived the journey unbeaten. But along the way he had conceived his next adventure: a motorcycle trip of even more epic proportions. He would ride deep into the mountainous California desert near the Mexican border, into forgotten places where his footprints would overlap those of forgotten Spanish conquistadores.

Another journey. A new adventure. A challenge that would allow him, in the end, to chase his demons back into the lake of fire itself.

Evan Tanner took on his first notable challenge – and, as became clear later, his earliest demons – many years earlier, on another remote roadside.

It was the 1970s, somewhere in Arkansas. He was about six years old, riding with his mother in the family's Volkswagen van while his stepfather, a man he regarded as a stranger, sat at the steering wheel. A tire blew out, forcing them to the shoulder. On closer inspection the parents realized they didn't have a working jack.

"What we need is a big, flat rock," the mother said.

The quiet boy spoke up. "I saw a big rock back there," he said, pointing back down the road.

"Get back in the car," one of the adults said. They returned to the task of lifting the crippled car.

It's impossible to say what passed through the boy's mind in that moment, beneath his buzz cut. Almost certainly, though, he sensed in those days that his family was fracturing around him. His father had left when he was a baby, and his mother moved in with his stepfather, but the boy and the new man never developed a relationship. Later his mother, who struggled with depression, would move out when Evan was in high school, leaving him to more or less raise himself while living with his older brother.

On this day, though, on an Arkansas roadside, Evan could do something.

His mother looked up and saw her little boy staggering toward them. In his arms he carried an enormous, flat rock, so heavy that his legs bowed under the weight. A rock that could, he hoped, solve their troubles. A rock to prop them up, if only for a little while.

He differed from other fighters in striking ways. He studied philosophy and felt he had a message to share with the world.

He grew up shy, so quiet in school that his classmates overlooked him. He loved to read and surprised his friends with a memory they all – to a person – describe as "photographic." He could learn how to replumb a house, fix a car, or analyze the major religions in just one reading. "He was an anomaly," one friend said.

His great intelligence came with great anxiety, and he often hid in the deep folds of a big sweater and cap, even during hot weather. His mild nature made him an easy target for bullies. His friend Deana Epperson, who grew up across the street, asked him once why he never fought back, and he told her he couldn't, "because God would be mad at me."

Then one day in middle school a pair of boys cornered him behind a dumpster and unleashed something larger and darker in him than they could have possibly understood. "He proceeded to whip them both, badly," Epperson remembers. "Nobody could believe it. Sweet Evan Tanner? In his penny loafers? We really didn't understand."

As he grew his physical prowess became undeniable. He excelled at pole vaulting, cycling, football, snowboarding, surfing, and even bowled a good game. He ran home from school each day, five miles. Midway through high school he took up wrestling, and in his junior and senior years he won back-to-back state championships. He appeared out of nowhere, the finest wrestler in the state of Texas.

"It was unprecedented," says Brent Medley, a close hometown friend who wrestled as well. "Most of those guys had been wrestling since they were knee-high, but none of us understood what Evan was doing."

As quickly as he had taken up the sport, he dropped it. Tanner's physical skill couldn't calm the restlessness that drove him, eventually, to become a self-described drifter – someone who, as he put it, had "gypsy blood." He left Amarillo to attend tiny Simpson College in Iowa, thinking of becoming a doctor, and he triumphed there by making the dean's list. Then, with no explanation, he left.

He roamed. He visited towns that interested him and made money doing hard, physical work: construction jobs, laying cable, day labor. He traded the strength of his body for a chance to feed his mind. And when anxiety came, as it did from time to time, he would find a poorly lit corner of some local bar and drink until the demons fell silent.

In 1997 he passed back through his hometown, Amarillo, to do some work climbing telephone poles, and he attended a fight of the sort that would eventually be called mixed martial arts. Tanner didn't particularly care for fighting as entertainment. But he did love the sense of battle. What could be more existential than two men grappling in a cage?

People in town still remembered Tanner for his wrestling as a kid, and a fight promoter approached him about climbing into the ring again. He gave it a try – and swiftly dispatched every hard-swinging hoodlum in sight. He fought three times in one night, winning a hometown tournament.

Encouraged, Tanner bought a videotape about grappling that featured the famous Gracie family of Brazilian jujitsu masters. He lived alone in a cabin in a Texas wasteland at the time, so remote that he powered his VCR with a generator. People laughed – what sort of rube teaches himself to fight by mail order? – but Tanner absorbed the leverage, the pressure, the physics of it all, just by seeing it done. Then he proceeded to lay waste to anyone who stepped up to meet him, working his way in one year from Amarillo to Japan, where he manhandled the Japanese in something called the Neo Blood Tournament.

He only needed one thing as a fighter: better opponents.

Tanner arrived at the UFC in 1999, at a time when it was trying to rehabilitate its underground image, and he couldn't have been better suited for it. Here came a handsome, articulate young Texan who looked like an athlete, not a street fighter.

Tanner thrived at the UFC over the next few years, bringing his professional record to 30-4, and in 2005 he gained a shot at the world middleweight title. He fought as an underdog against David Terrell, who early in the match placed Tanner in a painful "guillotine" choke. Tanner managed to escape, climbed atop Terrell, and pounded him until the referee called the fight for Tanner.

He was a world champion now living under the bright lights of Vegas, but none of it mattered to him. Ian Dawe, a Canadian fighter and friend who at one point lived for three months with Tanner, arrived to discover him living a monastic lifestyle in the heart of Sin City. Tanner had a one-bedroom apartment with one mattress – minus the frame – for himself and a futon for visitors, one plastic plate and cup for each, and a pile of books.

"He knew I wanted to see the glamour side of Vegas," Dawe says, "so one night when he was invited to a party at the top of the Palms, he went so I could have a look." There the young Canadian stared at UFC superstar Tito Ortiz, porn star Jenna Jameson, and other self-promoters who reflected light like disco balls, all teeth and cleavage and sharkskin. Tanner, a champion fighter, walked in wearing a T-shirt, blue jeans, and work boots. "He really didn't care," Dawe says. "And that shocked people."

Tanner had triumphed in mixed martial arts, and so, true to form, he abandoned the sport. His timing couldn't have been worse, really. The title bout had paid him only $38,000, but just afterward the UFC exploded into the national consciousness as a full-fledged sport, with millions of lucrative pay-per-view subscribers and much larger purses for its champions.

Tanner didn't care. Fighting, to him, had been like working in a construction yard or laying cable, but with an audience. "He never really wanted to be a fighter," his friend Brent Medley says. "That's the irony. He was good at it, but he didn't particularly like it. For him it was just a way of traveling the world. People recognized him on the street for his fighting, but he wanted to be remembered for his ideas."

Tanner had one particular idea that he wanted to convey to the world, which he called "the power of one." It's the notion of small kindnesses, or as he later explained: "Your words and actions resonate out eternally, in a sense. It reaches one person, then two people, then four, and it expands out exponentially."

The books in his apartment would have surprised the opponents whose faces he had pounded: 'Pride and Prejudice,' 'Doctor Zhivago,' 'Siddhartha,' 'Crime and Punishment,' and, most unexpectedly, 'The Tao of Pooh.' Tanner had always guarded his sensitive, philosophical side. Once, when he was in grade school, his mother had found him reading a biography of Chief Joseph, the 19th-century peacemaker. The boy had turned away, with tears in his eyes.

"Right now I'm just like a student," he said later, as a man. "I'm doing the best I can with what's put before me. Just getting ready."

Tanner decided to try the life of a sailor next, even though he'd never sailed. He tackled it in two steps. Step one: He bought a series of books about knots, rigging, navigation. Step two: He bought an antique 30-foot wooden-hulled, two-masted ketch.

His friends advised him against it. "It was crazy, but hey," says Jorge Gayoso, a Uruguayan boat repairman who worked with Tanner on his ketch in Oceanside, California. The two men, along with another friend, Dan Elliott, sanded and filled and painted the 70-year-old wooden hull and repaired the engine, and with time the three grew close. "That boat needed a lot of work," says Gayoso with a laugh.

Tanner and Gayoso hit it off particularly well. They were both wild men and scholars, tattooed thinkers who spent their days working on the old sailboat, riding their Harleys along the beach road, surfing, and arguing existential questions.

And in the evenings, Tanner drank himself into oblivion.

He always kept himself physically fit, but he'd been drinking hard for a dozen or more years. Once at a postfight party, Tanner – so shy when sober – picked up the wife of legendary UFC referee John McCarthy, then dropped her, hurting her head. The incident horrified Tanner, who fled further into alcoholism. Now he was drinking at an almost suicidal clip.

On the nights he couldn't make it back to his boat in Oceanside, he stayed with Gayoso or Elliott. Elliott worked a night shift as a physician's assistant and sometimes came home at sunrise to find Tanner starting into a case of beer. At midday he'd go out for another. Then a third, in the evening. Elliott felt powerless to stop him.

"Look," Tanner told him. "I drink harder and deeper than most people with a drinking problem could ever understand." He drank with a sense of purpose, calling it another challenge to himself. An adventure. He told friends he did it as an intellectual exercise, so that one day he could warn his own children – which he wanted someday, when he felt qualified – of the ravages of alcohol.

However worthy his stated aims, his actions undermined them. He sometimes slept on a park bench. His friends had to check his refrigerator to make sure he had enough to eat. His teeth started to loosen in his skull. Tanner was a good-looking guy with a strong jaw and blue eyes, but he grew a long, gnarled beard that gave him the look of a homeless man, which, in a sense, he had become. And the one subject Tanner never spoke about, even in the deepest stupor, was his own childhood: the abandonment, and the pain.

As months went by, Tanner and his wooden boat wore out their welcome at Oceanside's guest docks, so one afternoon he launched himself into the heavy swells of the Pacific, hoping to sail for a more forgiving destination. Elliott went along, worried his friend would die if left alone. He had only sailed once before, during a lesson.

About 10 miles out to sea the old boat hit a big wave – crack. Then came another: crack.

Elliott looked below, into the hull. "The bilge pump isn't pumping," he told Tanner. "This thing could go down, man."

Tanner leaped below the deck to see, and sure enough the whole ocean seemed to be pouring into the hull. He grabbed an old tool bucket nearby and began bailing out the water. "I stayed up all night," Tanner said later, "much of it spent down in the hold in the cold water, trying to save her."

He bailed water just long enough for the old boat to limp closer to shore, where a man in a dinghy rescued them. Then Tanner's boat sank in spectacular fashion, within sight of a San Diego marina. The episode made the pages of a local boating journal and then into mixed-martial-arts circles online, where it made Tanner a laughingstock among baffled fight fans.

Tanner publicly set a date to quit drinking: October 10, 2007. "And he did," Gayoso said. "He just quit."

Tanner felt he'd had a voice as a champion fighter and lost it when he started drinking full-time. So he started training again. He joined gyms in Oceanside and Las Vegas and set up a network of friends and fans he called Team Tanner. They were his sponsors, because he refused to wear the logo of any product he didn't believe in or use himself. Instead of slogans for energy drinks and online casinos, his T-shirts bore the phrase "Believe in the Power of One."

That astonished the mixed-martial-arts establishment. "I'd say, 'Evan, these people want to give you free money.' But nope," says John Wood, a fighter and owner of Warrior Training Center, where Tanner worked himself back into shape. "He could have made a lot of money."

Tanner returned to the UFC last March when he took on Yushin Okami from Japan. The fight's commentators noted Tanner's incredible return to form. "Got himself way out of shape," Joe Rogan said, ringside. "No training at all for two years. Just beer."

Few people knew, though, just how thoroughly alcohol had ravaged Tanner's body. His hemoglobin – the oxygen-bearing protein that gives blood its red color – had fallen dangerously low. On television he looked fine, but internally his body struggled to move oxygen.

The fight seemed balanced, for a while, but in the second round Okami wrapped his hands behind Tanner's head and brought it down hard, smashing it against Okami's upward-moving knee. Tanner dropped to the mat, unconscious.

"It's just so hot here," Tanner kept saying to his friend on the phone, as the temperature hit 115 degrees. "There's no water."

The second fight of his comeback ended only slightly better, when Tanner lost by split decision to American Kendall Grove. None of that really mattered. Tanner had triumphed again; he had drifted into drunken, sunken despair and then, at 37 years old, fought his way back to clear-eyed validation.

He searched, once again, for a more difficult challenge.

After that second comeback fight, Tanner took a break and rode his motorcycle to Oregon to see a girl. It was on that trip this past July that he forgot to check the fuel level in his bike and wound up pushing it back to civilization.

The woman, named Sara, had intrigued him with romantic talk of the desert. Tanner later wrote in his online journal:

I began to imagine what might be found in the deep reaches of the untracked desert. It became an obsession of sorts....

Today, I ran to the store to pick up a few things, and with the lonesome, quiet desert thoughts on my mind, I couldn't help but be struck with their brutally stark contrast to my current surroundings, the amazing congestion in which we exist day to day.

He described a plan to ride into the desert, where the emptiness of the landscape could allow him days or even weeks of reflection, like a modern Henry David Thoreau on his Walden Pond.

That sort of lofty, lonely talk made his fans nervous, and they said so online. Fighters should stay focused on their bodies. Their world is physical. And now Evan Tanner spoke of spooky things, of abstract treasures and existential congestion. Some fans wondered aloud whether he would die out there among the cacti and tumbleweeds.

"Come on, guys," Tanner wrote on his site. "This isn't a version of 'Into the Wild.' I'm not going out into the desert with a pair of shorts and a bowie knife, to try to live off the land. I'm going fully geared up, and I'm planning on having some fun."

Tanner set about preparing for his trek. He bought an enduro-style motorcycle, which he and Gayoso reconfigured for hard cross-country travel. They upgraded gaskets and put sealant in the tires. Rejetted the carburetor, attached aftermarket racks for his gear.

Meanwhile Tanner made a careful study of the desert, reading a whole stack of books about outback navigation, finding water, desert terrain. He shaved his beard and prepared to enter a landscape he called "crisp and clean, pure and shimmering."

He studied satellite images of the area where he planned to camp, marking a nearby spring from which he could replenish his water supply. And he gathered all the proper equipment, from batteries to water containers.

"Being a minimalist by nature, wanting to carry only the essentials, and being extremely particular, it has been a little difficult to find just the right equipment," he wrote online. "I plan on going so deep into the desert that any failure of my equipment could cost me my life."

On September 3, Tanner waved to a friend as he left his beach apartment in Oceanside, saying he might return in three days or three weeks. He planned on seeking peaceful solitude in the desert, however long it took.

He rode several hours inland, to the Palo Verde desert mountains, where he left the road and traveled across dry creek beds and through scrub brush. He pushed deep into the desert, into a valley. During the dry season even small animals struggled to survive on the washboard landscape, and signs in the area warned of a military bombing range.

There Tanner unfolded a small cot and chair, a sleeping bag, a water bladder, a handheld GPS, his journal, and two pens. He set up a tarp overhead, to ward off the sun.

On September 4, the day after Tanner left his apartment, Jorge Gayoso was wrapping up an afternoon's work at the waterfront, loading tools into his truck, when he received a text message that stopped him cold. It came from Tanner's phone:

If I don't contact you by 8 am, send out search and rescue. I am at Clapp Spring in the mountains west of Palo Verde. I set up camp a little south and east of Flat Tops.

As Jorge stood staring at the message – search and rescue? – a second one arrived:

I am out of water. Waiting for the sun to drop, then will try to hike the five miles back to camp. I feel like shit, but I'm okay. Gimme till 8 am, then worry.

Gayoso stared again. What had happened out there? He dialed Tanner's phone.

"Hey," Tanner answered. "I'm here, and–"

The connection broke.

Then Gayoso's phone rang.

"Man, it's so hot here," Tanner said. "I'm at Clapp Spring, but there's no water. So I'm just sitting here under a tree in the shade, waiting for the sun to drop."

Gayoso pieced together what had happened from what his friend told him next. On his first morning in the desert Tanner had decided to walk five miles to the spring he'd seen on the satellite images, where he could refill his water bladder. Five miles meant nothing to him; as an athlete he could jog five miles and hardly get winded.

"But it's just so hot here," Tanner repeated. By midday the temperature had reached 115 degrees. Even worse, outdated satellite imagery had deceived him; he had arrived at the spring to discover it was dry. So Tanner decided to hide from the sun beneath one of the desert's malnourished trees.

Worry rose in Gayoso's mind, but he spoke lightly. "Well, what are we doing here?"

Tanner said he planned to walk back to his camp after dark. Back to his motorcycle. He'd had enough of the desert.

The two friends bickered. Gayoso argued that Tanner should start walking out before dark so he could see any snakes, holes, or rocks, and wouldn't get lost.

Tanner, normally the gentlest friend imaginable, seemed annoyed. He noted he had a GPS. He'd be fine at dark.

"Do you have a flashlight?"

"No."

The connection broke again.

Heat is a strange thing. It makes men behave in strange ways and think strange thoughts.

Cold works in a more merciful way. When a man finds himself caught outdoors, exposed to very cold weather, his body urges him to slow down, to hibernate. He falls asleep in the snow and slips away.

Heat drives a man forward. It challenges him and awakens his mind. It makes him stagger forward, instead of falling asleep.

"People tend to fight for it, in heat," said David Pascoe, a professor at Auburn University and an authority on how the body reacts to temperature change. "Your body wants to unload that heat, which means increasing circulation. Which means movement."

When Evan Tanner woke up that morning he was probably already dehydrated. During the previous day's long motorcycle ride from the coast, the wind had secretly siphoned off a great deal of his fluid. When the sun came up and the temperature began to rise, a little cone-shaped part of his brain, the hypothalamus, sensed the change and sent word to his heart. The heart beat a little faster to move blood from his core to his skin, where the heat could dissipate. His skin was cooler because, in the meantime, the hypothalamus had directed the sweat glands to excrete water. Water that came from his blood.

It's an ingenious system: Blood circulates both heat and water. But the system is expensive. It costs fluid. Without incoming water the blood becomes more concentrated, which means there's less volume, which means the heart has to pump faster to move ever-thicker blood.

Pascoe conducts experiments with people's temperatures, dialing up the heat in a controlled way to see what happens. In one experiment, for example, he planned to raise his subjects' temperatures two degrees centigrade.

"The first degree was easy," Pascoe said. "We had them doing a sort of walking workload, no problem. Then in the next half-degree, suddenly people weren't so jovial. Not so happy. Then came the last half-degree."

People got aggressive, he said. They grew profane. They snapped, "Shut up! Leave me alone!"

At higher temperatures, he said, people lose their mental acuity. "I've seen people mumble about things with no idea what they were saying," he said. "It's bizarre behavior."

Dizziness sets in. Then disorientation.

All through the night Gayoso tried to reach Tanner. When morning came he remembered his friend's first message about search and rescue.

He paced his house in Oceanside, wondering what to do. Had Tanner's phone simply lost power? Or was it something worse? The whole thing seemed absurd. How does one even call "search and rescue"? He went online to look for a phone number.

A short while later, as sheriff's deputy Justin Hettich made a rare traffic stop outside Palo Verde, he received a call. A man with an Uruguayan accent wanted to read him a couple of text messages. Something about his friend. An ultimate fighter. Evan Tanner.

Hettich, other deputies, a search-and-rescue contractor, and a marine helicopter team searched the lonely countryside for Tanner's campsite. Even knowing his general position, they took a couple of days to find the tarp and motorcycle. Soon after they found his body.

He had made it almost four miles on the walk back to camp. He had sat down and taken pictures of himself, about 20 in all, right up to the moment of unconsciousness.

Then he had laid his head against a rock as if it were a pillow; not because he was sleepy but likely because in his dizziness the rock provided orientation. A rock to prop him up, if only for a little while.

Nature, in the end, forced him to submit.

In October, in Amarillo's dirt-floored cattle arena, a man with a microphone shouted a question to the crowd of about 4,000: "Are you people ready for a fight?"

Yes, they shouted. They were ready.

"I said, are you ready for a fight?"

Yes!, they shouted. And this time they meant it.

The fight's promoters had known Tanner and organized the event as a tribute. They invited his family into the cage, then announced the creation of a college scholarship in Tanner's name. The moment came with some awkwardness; Tanner hadn't spoken to his family in years, and his friends say he didn't care for them very much.

Tanner's mother, Sue Craig, is reluctant to talk about her son. "I guess what I'm wondering is, what's in it for us?" she says. There may be money down the road, she explains, when Hollywood gets word of Tanner's life.
She offers some broad sketches, some sense of how his childhood had unfolded. The father gone, the mother gone. The cold relationship with the stepfather.

She pauses, then adds, "I'm not sure how that's relevant, though. I'm not sure that affected him."

Except of course it did. Throughout his life Evan Tanner drifted – geographically, emotionally, physically – searching for a home. Searching to calm his restless mind, to prepare himself for a fatherhood that never came, to discover a purpose for his great and varied talents. And then, when he came near to any acceptance, he abandoned it.

The crowd in Amarillo was getting twitchy, after a few undercard matches and innumerable beers. Fights broke out in the audience and drew as much attention as the contests in the ring. A rowdy bunch, spoiling for action. Then, almost at the end of the night, Evan Tanner appeared on two giant screens, at each end of the stadium. When the crowd saw him they exploded with cheers. "Evaaan! Evaaaaan!"

His soft-spoken voice filled the place. He had something to say.

"One of the ultimate things a human can learn," he said, "is kindness for their fellow humans."

He might as well have delivered 4,000 simultaneous knockout punches, so complete was the silence.

Onscreen he paused. He looked down, as though speaking to himself now.

"I'd like to teach those things to my children."

The great tragedy of Tanner's life, in the end, was that he was right about himself. In each of his endeavors – his adventures, his challenges – he was indeed only a student, preparing for some later task. But that was also his greatest triumph: At the end of his posthumous message in Amarillo, the restless, hard-bitten crowd rose to its feet and cheered, against all likelihood, for the abstract cause of simple kindness.