THIS SPRING, AFTER 16 YEARS OF EFFORT, Ed Viesturs became the first American to climb all 14 of the world's 8,000-meter peaks. Fittingly, the 46-year-old Seattle-based mountaineer's quest ended with Annapurna, the first 8,000er ever climbed.

"I was in high school when I read Annapurna, and it really inspired me," Ed said when I called to congratulate him. Annapurna, by Maurice Herzog, is the romantic account of the first ascent of the 26,545-foot Nepalese peak by a 1950 French expedition. "It had everything," Ed continued. "Camaraderie, bravery, sacrifice, perseverance. That's the book that got me into climbing. I grew up in the great mountaineering state of Illinois and moved to Seattle right after high school. I could see Rainier out my dorm-room window. That was my Annapurna then."

It took Ed three tries before he summited Annapurna, just as it had taken him three attempts to summit Everest. He is only the 12th person to climb all of the 8,000-meter peaks; this accomplishment alone would not be that notable but for one salient point: Ed climbed all of them without supplemental oxygen, most in alpine style, with little or no help from Sherpas. (Like Ed, I have made it a habit to climb without O².)

"From the beginning, I made a decision that if I couldn't do it without oxygen, I wouldn't do it," Ed told me. "It was a personal choice. Could I train myself to meet the demands of climbing at high altitude? Could I train my mind? It wasn't just about getting to the top; I wanted to experience what it felt like up there. Going without oxygen was more interesting, more challenging—technically, physically, and mentally." Ed is the first to acknowledge his debt to Tyrolean alpinists Reinhold Messner and Peter Habeler, who pioneered the first oxygenless ascent of Everest, in 1978. (Messner became the first climber to summit all the 8,000ers, in 1986.) At the time, naysayers predicted that Messner and Habeler would suffocate to death or suffer brain damage. Apparently none of these pundits had read their history.

Millions of words have been written about 1924's Third British Everest Expedition, in which George Mallory and Andrew Irvine vanished into thin air, leaving unresolved the possibility that they had summited. And yet the most significant achievement of that climb has been all but overlooked: Four days before Mallory and Irvine made their fatal, oxygen-assisted attempt, expedition leader Lieutenant Colonel Edward Norton had climbed to within 909 feet of the summit of Everest without oxygen.

Norton and his partner Howard Somervell left their high camp on a windless, beautiful morning. Climbing steadily—through the Yellow Band, traversing the upper North Face—they reached the final summit pyramid by noon. Somervell became too ill to continue, but he encouraged Norton to press on. Norton was wearing hobnail leather boots, a tweed jacket, wool knickers, and a felt hat. He wielded a single wood-shafted ice ax; he didn't have a rope, crampons, a down coat, Sherpas, or oxygen. Because he had removed his snow goggles to cross the black rocks of the North Face, Norton's eyes were sunburned, but nonetheless he continued upward without Somervell.

At 28,126 feet, exhausted from the delicate, perilous climbing and realizing that he was going snow-blind, Norton turned back. No human would go higher until Hillary and Norgay, using supplemental oxygen, reached the top of Everest in 1953. No human would go higher without oxygen for more than half a century, until Messner and Habeler in '78.

But what if Edward Norton had summited Everest in 1924, solo, without oxygen? Not only would it have changed the history of Himalayan mountaineering completely; it would have set an entirely different precedent for the style in which high mountains are climbed.