All morning on October 23, 2006, the two men worked out moves on Leaning Tower, a jagged tooth of gold and yellow stone that rises about 3,000 feet from the valley floor of Yosemite National Park. Todd Skinner and his climbing partner Jim Hewett, friends since 2001, were mapping out a first free ascent on the gigantic wall. Plenty of others had spidered to the top of Leaning Tower by popular routes such as the West Face and Wet Denim Daydream, but Skinner, typically, had his sights on an unclimbed route, branching off to the left of Wet Denim, that he and Hewett could claim as their own.

The project was ambitious, requiring weeks of preparation, one stolen week at a time, to spend hour after hour finding new hand- and toeholds, clearing the rock of plants and loose stones, "choreographing" the upward movements, before Skinner and Hewett would finally attempt the whole feat, perhaps a year later, in a single sustained push from the bottom to the top. Such slow and painstaking work isn't for everyone. "It's surprisingly hard to find people who are willing to do that," says Hewett. "But that's what we loved."

That morning Skinner and Hewett got plenty of what they loved. The weather was perfect – windless, cool, and cloudless – and the partners tackled the most challenging parts of the face, the "crux" pitch of the climb. Even so, by two in the afternoon it was too hot to continue, and they called it quits for the day. They descended to a narrow ledge about halfway up the wall, ate the sandwiches they'd brought in their backpacks, then began to rappel down to the bottom. Skinner went first. He had neared the end of his second rappel when Hewett, a hundred feet above, heard a snap-slap sound.

"I looked down really quickly and just saw him falling," Hewett says. He heard no cry – just eerie silence as Skinner dropped 500 feet to the ground below. "On the way down I saw him bounce once and then land," Hewett says. "And I knew he was dead."

News of Todd Skinner's death, at age 47, first broke on supertopo.com, the popular climbers' website. "WHAT?" read one post. "I hope this is a troll."

Within minutes more posts brought confirmation of Skinner's death, followed rapidly by scores of tributes to him. The posts attested to his tenacity, his generosity with other climbers, and, above all, how psyched he always was. "Todd was one of the funniest, most...upbeat guys I've ever encountered in the sport," read one entry. "The energy man...it was all about the energy, and he had it."

"Todd was a couple of decades ahead of his time," says Bobby Model. "But more important than any of his innovations, he exuded this force field of energy that made you feel like you could basically do anything." Model, 34, a photojournalist based in Kenya, joined Skinner on several committing climbs. "Todd was unusually generous," Model adds. "When climbers reach a certain level, they're usually a little impatient with people who are just starting out, but not Todd. He'd take an interest in you if you were climbing 5.6" – on the scale of climbing technical difficulty – "or 5.14. He didn't care, he just wanted people to exceed their level." Skinner's death, Model says, came as a shock. "He was very safe, always double-checking, always communicating....He never took unnecessary risks."

Even as friends and acquaintances expressed their grief – and his death was not only a terrible loss for rock climbing, but for his wife and three grade-school children – no one with any knowledge of the sport could accept how the accident had happened. According to authorities in Yosemite, Skinner's belay loop – a small but extremely rugged nylon ring on a belt harness to which climbers attach their ropes – had simply given out, shorn right through. This suggested either an unfathomable equipment failure (few could even recall a precedent in the history of the sport) or an equally unfathomable lapse in judgment. The great Todd Skinner, dead from an old, frayed harness? No way. Must be some mistake. Or there must be something we don't know.

The disbelief was understandable. Until that October afternoon, Skinner had cheated death for more than a quarter century, willing himself up sheer rock faces and peaks in some 30 countries, including Vietnam, Pakistan, Venezuela, and Mali. He once took 80 days, almost three solid months, to complete a single, stunning first ascent, and he was famous for his "mono" – lifting his entire body weight on a single finger. He really did seem invincible. Irrepressible, too: Unlike his fellow climbers, many of whom thumb their noses at fame, Skinner was a shameless self-promoter who made no secret of wanting to get paid to travel and climb full-time.

He succeeded, becoming among the first to do so. Eager to popularize rock climbing, Skinner grew with the sport throughout the 1980s and early '90s, and while he may not have dominated climbing as Michael Jordan did basketball, Skinner was, like MJ, the face of his sport. "Rock climbing up to the late '80s wasn't a mainstream sport," says Jonathan Thesenga, the former editor of 'Climbing' magazine. "It was a full-on death-defying sport. People didn't get it, and that was part of the allure. It was fringe. Todd was trying to bring it into the mainstream, and people were saying, 'No, this isn't a mainstream activity.' And he's like, 'Yes, it can be.'"

At the same time, Skinner was intensely controversial, and not just for his notoriety. In the '80s Skinner championed an approach to the sport known as "free-climbing," in which climbers rely upon ropes, rope ladders, bolts, pitons, or other aids only for safety – in case of a fall – but not to advance up the rock. Because elevation gain was derived from the problem-solving skills and physical effort of the climber, Skinner argued free-climbing was purer than conventional "aid" climbing. But critics, some of whom went to the trouble of spying on him through telescopes as he climbed, charged that Skinner relied on external aids plenty to "rehearse" his free-climbs, exaggerated his achievements, and made up the rules as he went along in order to claim more firsts for his climbing résumé.

Beneath all the froth about climbing purity, though, Skinner was engaged in a project he took quite seriously: discovering his ultimate "capacity," as he put it, as a human being. To reach beyond what any of us believe ourselves capable of – this was Skinner's dangerous, addictive, and inspiring game. It drove him to nearly unimaginable feats, but it appears to have been his undoing as well.

In the beginning Skinner wasn't supposed to be a climber but a skier, and not just any skier, an Olympic medalist. His father Bob was one of six sons of Clem Skinner, who'd moved from Wisconsin to Wyoming in 1925. One of the brothers was on the U.S. Olympic biathlon training team in the 1960s, while two others started a ski racing foundation at the Jackson Hole Mountain Resort. Bob, the third son, taught survival skills in the air force after World War II and was a competitive downhill skier. In 1956 Bob and his brothers opened a wilderness survival school, called Skinner Brothers, in their native Pinedale, Wyoming; they ran the school for almost five decades.

Todd, born in 1958, was the middle of three children; he joined his older brother and younger sister as regulars at the school and completed the survival course multiple times. His father Bob recalled seeing a Wild West show in Jackson with Todd, then eight years old. A rough-looking "bad guy" who had just performed in a shoot-out leaned over Todd and growled, "What do you want to be when you grow up?" Todd did not blink. "A giant!" he declared.

Climbing got an early hold on Skinner. At 11 he became one of the youngest people ever to summit Gannett Peak, the highest point in Wyoming, a 13,804-foot mountain that took him 14 hours to climb. He also devoured stories about famous explorers such as Robert Scott and Roald Amundsen – obsessed, he later wrote, with understanding "what people are capable of enduring."

He didn't have to wait long to get his own first "glimpse at how far you can really go," as he later wrote in his memoir/primer Beyond the Summit. At 19 he got in way over his head on a winter mountaineering trip. Out in the backcountry with an uncle and some others in late 1978 for a winter ascent of Gannett Peak, they blundered onto the wrong trail and found themselves stranded without water, tents, or food in subzero temperatures. They eventually made it back to camp after several days. "Even at the time," Skinner wrote, "I sensed it was a worthy investment into my future capacity."

In 1977 he enrolled at the University of Wyoming, where he studied business and finance and joined the ski team. "He got a lot of – I won't say family pressure – but family incentive to be a skier," says Brad Werntz, who had befriended Skinner when he attended Skinner Brothers. But Skinner soon met fellow undergrad Paul Piana, who had grown up in Wyoming near the Black Hills of South Dakota and who had been rock climbing since childhood.

Piana would practice on a decorative sandstone wall in the school's cafeteria, using the wall's shallow finger- and toeholds to traverse back and forth. Under Piana's wing Skinner learned climbing quickly; by his senior year he had decided to abandon skiing and devote his life to climbing.

In 1979 the two took their first road trip to Yosemite, where they were surprised to discover the ease with which they could master some of the most famously difficult routes.

"We had imagined it to be so impossibly difficult that we had trained correspondingly hard in preparation...and we ended up much stronger than we had to be," Skinner recalled in his memoir. "We were shocked by our success." Though the pair were still unknown, they were ambitious, and they saw lots of room to make their mark.Among nonclimbers climbers are often confused with mountaineers, guys like Edmund Hillary, Reinhold Messner, or Ed Viesturs, who have taken on the world's tallest peaks. Skinner made a few expeditions at high altitude, but he was a rock climber, not a mountaineer, and thus a member of a diverse community of athletes who scale near-vertical faces of varying sizes by various means – and who debate those means vigorously. Because their sport requires great devotion, even privation, climbers tend to eschew material comforts and take pride in living poor (Dumpster-diving, if need be); they take even more pride in self-reliance (real climbers don't call rangers for help).

For the sake of argument, the rock and ice climber Will Gadd has divided rock climbers into distinct "tribes." There were the unruly, unwashed big-wall climbers who laid siege to the 3,000-foot granite monoliths with all manner of devices and spent weeks hanging off rock from pitons they'd hammered in; sport climbers who scaled lower (about 100-foot) faces, many with bolts for ropes looped to a belay partner on the ground; and trad – traditional – climbers who, as Gadd notes, "[believe] that the bolts common to sport climbing are sacrilegious" and climbed with the use of removable cams and chocks instead of hammered pitons and bolts in order to leave the rocks as they found them.

Skinner didn't care much for the semantics of these tribes, and he'd piss off the guardians of each discipline in due course, but he was unmistakably one of them, too, committed to the dirtbag, nomadic, monklike existence of climbing's answer to the ski or surf bum. In his 20s, in the 1980s, he met many of his girlfriends in campgrounds or on rock faces; if they stuck with him it was because they shared the romance of the mountains – even if it meant living out of their boyfriend's VW van.

"That was just how we lived then," says Beth Wald, a photojournalist who was Skinner's girlfriend for a few years in the mid-'80s. Skinner, she says, "didn't really care if people agreed with what he was doing... He was just focused on 'sending' his next project." She saw him act impatiently only with people "who lacked passion" in their lives. About the only thing he was touchy about, she laughs, with affection, was his hair, which had started thinning at an early age, leading him to cover his hairline with a (soon ever-present) bandanna.

For years after college Skinner and Piana held real jobs only long enough to save gas money for another trip to, say, Hueco Tanks, Texas, now a popular spot for bouldering (climbing low to the ground without ropes but using pads below). Eventually, the two hit on an MO that borrowed from several climbing tribes. They took the approach of sport climbing – bolts and other protection placed at intervals, with a partner on belay to break a fall – and applied it to really big walls, in sections. Then, once they'd scouted out a new route putting these sections together, they'd "free" it – without aid – in one sustained push.

One of the great advantages of the duo's commitment to free-climbing was that it allowed them to claim first ascents of walls that had been climbed previously, but by conventional means. The two rarely missed a chance to make such a claim; by the time of his death Skinner counted no fewer than 300 first ascents.

As if all their claims to true firsts weren't enough to raise some hackles (and was it really free-climbing, asked doubters, if they used bolts to scout the route?), Skinner tossed in a still more divisive innovation.

In the late 1970s and early 1980s the unwritten rules of free-climbing stated that if you slipped, fell, and were caught by your safety ropes, you returned to the bottom and started over. But Skinner used a different approach: If you fall, you hang from your ropes, recover, then practice the move repeatedly until you master it. The technique is known as hangdogging, and when Skinner pioneered it in Yosemite, he loosed a shitstorm, gaining the nickname "Turd Skimmer."

Skinner never let the abuse get to him. Some years later, when park rangers at Hueco decided that drilling new bolts into rocks was vandalism and targeted Skinner as an outsider with a big reputation, Skinner took to carrying around a waffle iron and other heavy metal objects in his climbing pack to make enemies think he was going to drill and bolt a sacred bit of rock. They would call the authorities, who would ask to see his stuff and find...a waffle iron. Even the most righteous scolds had to laugh.

Skinner stunned the climbing world in 1985 by freeing a seemingly impossible Yosemite crack called the Stigma. He and Piana then set their sights on the project that is still considered their signature – and most disputed – achievement: a free-climb of the Salathé Wall of El Capitan, the 3,604-foot monolith in Yosemite.

Until then, the longest climb Skinner had done was six pitches; the Salathé has 36. In 1988, after months of planning, he and Piana traveled to Yosemite and spent a month choreographing moves. To free his mind of the fear of falling, Skinner took deliberate 30-foot falls, coming to bouncing stops at the end of his rope, a tactic Skinner called "getting velocitized."

After the month of preparation, they made their assault: a seven-day marathon that brought them to the summit. Yet no sooner had they reached the safety of horizontal ground than they were nearly crushed and swept to their deaths.

At the summit, Piana had anchored the ropes holding their heavy equipment (tents, packs, food, stove) to a huge stone block. Skinner posed for a quick picture. They were about to start down when they heard a crack. The stone block had broken off at its base and was grinding toward them at the cliff's edge.

Skinner tried to lunge out of the way, but a loop of slack rope caught him and, pulled by the falling rock, squeezed the breath out of his lungs. He feared being "cut in two" when suddenly the moving block severed the constricting rope, launching Skinner over the edge. "Miraculously caught by one uncut rope, I dangled below the rim," he recalled later, "and [I] watched the block slowly go over, just kissing my shoulder on the way down."

Piana's own published account describes the "horror of seeing my best friend knocked wildly off the edge"; he felt a punishing weight on his left leg and was himself "squeegeed off the rim," but he managed to scramble back onto solid ground. He assumed Skinner was a goner, when he heard a tiny, squeaky voice coming from below the edge of the precipice: "Grab the rope!" Seconds later he saw Skinner's bloodied hand grab the rim. Piana helped him up and the two lay panting in pain.

Skinner had two broken ribs and was coughing blood. He'd torn a muscle from his hip and could not lift his left leg. Piana's leg was crushed. They waited for rescuers, unaware that people on the ground had seen their packs and clothing fall from the mountain and thought it was the climbers themselves. The rescuers were searching for their bodies at the bottom of the cliff. Skinner and Piana were left to crawl with their broken bodies down the mountain as night fell. It took them almost seven hours.

After his and piana's painful success on El Cap, Skinner, now 29, got his first taste of life as a yuppie instead of a dirtbag. Ann Krcik, then working at the North Face, helped complete a deal that made him only the second athlete to be put on the company's retainer. "He had a charisma unmatched by anyone else," says Krcik, who went on to become director of marketing operations before founding a corporate speaking agency, Extreme Connection, with Skinner as her main client. "He was a natural-born storyteller."

Certainly Skinner gave good quote. Mountains, he said, "are powerful narcotics. They can wreck lives and end marriages. And they never diminish in importance." Because free-climbing required avoiding devices, it was "a ballet where you are both the choreographer and the dancer." More than happy to shock his audience, he would tell them about how he and his team once resorted to eating monkeys in the jungles of South America because an airdrop of food hadn't landed. "They tasted like burned hair," he said, "because we didn't know how to skin them."

Skinner appeared in magazine ads for clothing and gear, dangling from rock formations or with his ripped forearms crossed, his wind-whittled features in a trademark grin. He also hustled for exposure on TV adventure shows to help underwrite his expensive expeditions.

Even climbers who respected Skinner sometimes balked at his willingness to airbrush the realities of climbing in the interest of winning a mass audience for the sport. Lynn Hill is a world-renowned climber who counts herself as one of Skinner's friends and professional peers. (Skinner visited her in Boulder after the birth of her son in 2003, when he was passing through the area.) At the same time, she understands why Skinner drew fire.

"He did posture in certain ways," she says, "and some people have negative personal stories." But Hill says the closest thing she has to a negative story occurred on a climbing trip with Skinner and a few others in Vietnam in 1996. A cameraman came along to film a documentary, but Skinner told him not to film team members placing bolts in the rock as protection. "When people see bolts they say, 'Oh, that's no good,'" Hill says. "He wanted to present our experience in Vietnam in a certain way. He was definitely a showman."

Such PR-savvy tactics paid off for Skinner. In 1989 Apple Computer invited him speak at one of its sales meetings. Before 3,000 people at San Francisco's Civic Center, he told the story of free-climbing the Salathé. He got a standing ovation. Soon he was doing as many as 30 talks a year, all over the country, earning up to $20,000 a speech. Once a penniless nomad, Skinner became wealthy, buying homes in several of his favorite climbing areas: Hueco Tanks; Groveland, California, near Yosemite; and Lander, Wyoming, which became his permanent home.Skinner first learned about Lander in 1989, when his sister Holly, a gold prospector, discovered in the nearby foothills a wall of limestone cliffs that reminded her of those that Skinner had loved to climb in France. She wrote to tell him to come check out the virgin faces, called Wild Iris. Sure enough, Skinner did love them and summoned Piana, who came with his then-girlfriend Heidi Badaracco, an expert climber. Skinner rented a small house with Amy Whisler, the woman who would become his wife.

Born and raised in Las Vegas, where her father had a job taking delinquent youths into the mountains on climbing and hiking expeditions, Amy had grown up much as Todd did: scrambling up rock faces and looking for adventure. She supported Skinner's lifestyle wholeheartedly and joined him on many of his quests. The two bought a place in Lander, and opened up a climbing and outdoor equipment store, named Wild Iris after the local walls, and married in 1999. In 1998 their first child Hannah was born, followed by twins Jake and Sarah two years later. Even then Amy did not stand in Skinner's way when he sought out distant climbs and traveled to give speeches.

"Amy sacrificed," says Skinner's friend and frequent climbing partner Steve Bechtel. "As driven as Todd was on his climbs, you needed someone just as dedicated back home. So he was very lucky he hooked up with her."

Skinner and Piana didn't have the cliffs of Wild Iris to themselves for long. "Word went out through climbing magazines that Todd Skinner was climbing in Wyoming," says Bechtel. Soon climbers flocked to Lander. Skinner welcomed the influx, and when he decamped to Texas's Hueco Tanks for the winter he invited his new friends along. Eventually he built a house there, one that could sleep 20 people. "Seven tiny bedrooms and a bunk room with eight bunks," says Amy. "Like a commune."

Skinner delighted in the company of veteran and novice climbers alike, but he also remained maniacally focused on his own personal climbing goals. After the Salathé he and Piana hatched a plan to climb the three other major walls in North America: Mount Hooker in Wyoming, Mount Proboscis in Canada, and the northwest face of Half Dome in Yosemite. He and Piana achieved the first two goals with relative ease, but on Half Dome's 2,400-foot northwest face, they stalled. After finishing the first two pitches, they hit a blank wall of smooth stone devoid of holds. They spent 20 days trying to find a way up; then Piana quit. Skinner went through three more partners and 30 more days of trying, to no avail. Fifty days into the ordeal he talked Steve Bechtel into coming to Yosemite. Bechtel brought Canadian climber Chris Oates with him, and the three finished the wall in 10 days. Bechtel was stunned by Skinner's commitment.

"It's so easy to get discouraged," he says, "because if you try something and you fail, your feedback loop is 'I'm not good enough to do that.' But this guy would fail 60 or 70 or 80 times – for 80 days – and still wake up in the morning ready to go."

Skinner's most extraordinary feat, however, was still ahead. In 1995, after two months of living in hanging tents and subsisting on rehydrated food and dodging ice storms that killed climbers on neighboring peaks, Skinner and a handful of "Wyoming cowboys" managed to free-climb the Trango Tower, a 3,000-foot spur of granite reaching 20,469 feet into the frigid air above northern Pakistan. The mountain presented challenges unlike any a free-climber had ever faced. But for Skinner, everything about Trango was pure joy.

"[T]here is a validation that comes with sheer terror," he later wrote, "because you know then that you are playing in an ultimate arena."

The problem was that after a lifetime of seeking out the next challenge, he was suddenly bereft of new goals equal to his last. "In a way," he wrote in 2003, almost 10 years after that ascent, in a rare admission of existential unease, "Trango was my 'last next.' I could imagine nothing beyond it."

When skinner decided to tackle Leaning Tower last fall, he knew he was aiming high, and he knew he wasn't as powerful as he had been. "We talked about it a little bit," says Bechtel. "It was something he was really struggling with. He was still climbing very, very well – and as well as anybody who is 47 anywhere in the world – but he could see that there's a horizon there. He was starting to get injured, and you could tell it bothered him."

Skinner's wife Amy agrees. "He just never had injuries," she says. "He had a shoulder injury a few years ago. It was the first really bad injury I'd ever seen him have. He was considering surgery." Even so, Amy did not tell him to back off. "The optimism was huge," she says, "and that was true to the very end of our life together. It was, Never settle. Just go for the most you can possibly be."

The issue wasn't merely whether Skinner was in shape, physically, to attempt such a climb; he also carried heavy emotional burdens. Weeks earlier, on September 20, his mother died after a long battle with cancer. Tragically, his father had also been diagnosed with the disease, and Bob Skinner, one of Todd's great heroes, was now at home in Lander, dying.

I met with Bob in mid-November, just weeks before he succumbed to cancer. In a tidy house that bore pictures of Todd on granite faces, Bob, who was hooked up to an IV drip, spoke with uncommon composure about his son. "I'm having a tough time believing it," he said. But like Amy, he had supported Todd in his continuing quest for climbing glory. "I was encouraging him to go for it," Bob told me. "To go for anything."

Skinner had warned Jim Hewett that he might have to abandon the Leaning Tower climb if his father's condition deteriorated. His father, however, was not his only family obligation; his twins' birthdays coincided with Skinner's time in Yosemite. He had made plans to fly back for a few days to celebrate their birthdays, then return to the tower.

On October 14 Skinner met Krcik to drive into Yosemite. On October 19 as he and Hewett got ready to climb, Skinner showed Hewett his climbing harness; it was badly worn. "He was so much about getting it done," Hewett reflects, "he wasn't going to let that stop us." Still, Skinner's harness, an Arc'Teryx model from 2002, "was the worst I'd seen him in ever. If it had been my wife, I would have made her tie a backup loop or change the harness for sure. I probably wouldn't have let her go up in it. That being said, he and I both understand that this stuff is over engineered, and also he's alive after doing it this long. You've got to think, 'Okay, he knows what he's doing.'" When he told Skinner the harness looked worn, Hewett recalls, "he was, 'Yeah, yeah, I've got a new one coming.' That was the last we spoke of it."

They climbed without incident for three days, but on the fourth afternoon Hewett heard the snap, and Skinner plummeted. There was a party of climbers on a route up to the right, about 500 yards away. Hewett yelled up to them, telling them what had happened. Two of them were members of Yosemite search-and-rescue and said they would call in Skinner's fall. Hewett began to descend.

Two rappels later he was on the ledge where Skinner's smashed body lay. "I didn't – didn't really go over and look," he says. "I just saw his foot sticking up and some other stuff. I yelled, and he didn't answer."

Amy's decision about what to do with Skinner's body had been made a couple of months earlier, when Skinner had been enlisted by the local search-and-rescue to look for a lost climber. Skinner had found the man, dead after a 500-foot fall. "That poor man's body was beat to pieces," says Amy, "and Todd said, 'I don't want the family to deal with that.' Todd and the pilot made the call that the body should go into town, not to where the family was. Todd said, 'You need to remember the person he was, not the horrible mess,'" says Amy. "So when it was my turn to make those decisions, it was a no-brainer. He was cremated."

Although the harness did break, Amy says she had no intention of seeking damages. "Todd used all of his gear harder and longer than he should have... If there's any blame in the accident, it's Todd's." Amy has spoken to Arc'teryx, and believes "there's no fault at all, in terms of the company that made it." Even so, "It shouldn't have happened. It was an accident." (Arc'teryx president and CEO Tyler Jordan confirmed that his company made the harness and said Arc'teryx had cooperated with the National Park Service's investigation.)

Suggestions that Skinner was too impatient to wait for a new harness, was pushing to fit the climb in before his twins' birthdays, or that he was distracted by his mother's recent death – these don't go over well in Lander. Nor will anyone concede that Skinner might have died because he continued to attack walls that were beyond his capacity, now, to climb. No one wishes to believe that age, injury, or grief over a dead mother and dying father might have contributed to his fall.

Of course, Skinner did not die on the actual climb, but climbs as demanding as the one on Leaning Tower require total investment from a climber – whether he is on the ascent or simply returning to base camp. "I happen to know," says climber Hill, "that when people are emotionally stressed or distracted like that, they don't make the best decisions."

Werntz is convinced that his friend's fatal decision to climb with a frayed harness did not stem from his emotional state. "Oh, absolutely not," he says. Hewett takes the same line, but admits some doubt. "He was pretty good at blocking things out so he could climb."

The reluctance to see Skinner as fallible makes sense. For so long he had embodied an optimistic, positive ethos: the refusal to succumb to limitations. Yet age makes its inevitable claims. Despite all of Todd Skinner's hard-won wisdom, this was a lesson the mountains could not teach him.