Climbing Mount Everest, the tallest mountain in the world, was a challenge that eluded scores of great mountaineers until 1953, when Sir Edmund Hillary and Tenzig Norgay first reached its summit. Over the next three decades, more "firsts" followed, including the first ascent by a woman, the first solo ascent, the first traverse (up one side of the mountain and down the other) and the first descent on skis. But all of these climbers had relied on bottled oxygen to achieve their high-altitude feats. Could Mt. Everest be conquered without it? As early as the 1920s, mountain climbers debated the pros and cons of artificial aids. One, George Leigh Mallory, argued "that the climber does best to rely on his natural abilities, which warn him whether he is overstepping the bounds of his strength. With artificial aids, he exposes himself to the possibility of sudden collapse if the apparatus fails." The philosophy that nothing should come between a climber and his mountain continued to have adherents fifty years later.

In the 1970s, two of its strongest proponents were Reinhold Messner and Peter Habeler. Messner had achieved considerable notoriety by completing a series of spectacular Alpine rock climbs without the use of metal protection pegs. In 1974, Messner teamed up with Habeler, a quiet Mayrhofen guide who shared his philosophy, and the pair proceeded to take the climbing world by storm. Agile and slight of build, they scaled the Matterhorn and Eigerwand faces in record time. In 1975, they made a remarkable ascent of the 11^th highest mountain in the world, Gasherbrum, without using supplemental oxygen. By 1978, they had set their sights on climbing Mt. Everest—without bottled oxygen.

Messner and Habeler quickly found themselves the subject of criticism by members of both the climbing and medical communities. They were labeled "lunatics," who were placing themselves at risk for severe brain damage. The physiological demands of climbing Everest had been studied on previous expeditions, and found to be extreme; in 1960-61, tests conducted on members of an expedition led by Sir Edmund Hillary concluded that oxygen levels at the summit of Mt. Everest were only enough to support a body at rest—and that the oxygen demands of a climber in motion would certainly be too great.