Chilling catharsis of death on Everest
It is called - melodramatically, but with chilling accuracy - the Death Zone.
Once a climber ascends above 7,000 metres on any mountain, he or she is living on borrowed time.
The lack of oxygen at high altitude means a mountaineer is prone to hypoxia, a condition in which the mind and body begin to shut down.
The thin air can also bring on fatal cerebral or pulmonary oedema - water settling on the brain or flooding the lungs.
Add to this the constant threat of hypothermia in the mind-numbing cold and searing winds on top of the world's highest peaks, plus the treacherous icy conditions.
And it becomes clear why high-altitude mountaineering is so staggeringly dangerous.
This grim lesson was starkly brought home in May last year when eight people died on Mount Everest in one 24-hour period - what became the darkest day in the history of climbing the world's highest peak.
One of those to survive was Jon Krakauer, a journalist and experienced low-altitude climber from Seattle, who had been commissioned to write a piece on the growing commercialisation of the mountain.
A decade ago, climbing Everest was the preserve of the world's top mountaineers.
But in recent years the rich and comparatively fit have been able to battle their way to the top with the aid of experienced guides and copious supplies of bottled oxygen.
Krakauer joined a guided group, most of whom had paid US$65,000 (about HK$500,000) to take a crack at the mountain.
Four members of his expedition - including two of its guides - were to die during a storm as they tried to battle their way down from the summit.
In his introduction, Krakauer writes that he is still haunted by what happened on Everest last May and this book is testament to that fact.
The author goes into painstaking detail about the events of those 24 hours and attempts to make sense of it all - an act of catharsis and trying to come to terms with what happened.
But, on finishing this account, with its appropriately taut, bleak and uncompromising prose, one suspects the author has found little meaning or solace in his companions' deaths.
Several key facts emerge: first, many of the climbers were struggling their way to the top far too late in the day.
Krakauer's group was led by New Zealander Rob Hall, 35, an experienced mountaineer and Himalayan guide.
As the team made its push for the summit, Hall was at the tail-end of the group helping one of his clients, Doug Hansen, a 46-year-old American postal worker who had been forced to turn back within sight of the summit the year before.
Hall had persuaded Hansen to return for a second attempt on the mountain and, despite the fact that the American was struggling and that time was ticking away, the two men continued to battle their way up the mountain well into the afternoon.
When the storm blew in, these two - along with members of an American-based group - were stranded on the peak. Their hours were numbered.
Hansen soon died, and Hall survived long enough to make one last emotional telephone call to his wife in New Zealand.
Krakauer also makes the point that many members of the guided groups on the mountain were not up to the task.
At one point a Sherpa had to haul an American socialite, Sandy Hill, up some of the mountain's higher reaches with a short rope.
Hill disputes how long she was assisted for and maintains she was in no difficulty, but Krakauer's implication is clear.
Once clients got close to the summit they were loath to turn back, even if time and their physical condition were not on their side.
Krakauer says people have a natural tendency when looking at disasters to try to establish what went wrong so as to ensure something similar never recurs.
But he questions whether this approach can work when looking at climbing Everest or, indeed, any of the world's highest peaks.
Krakauer writes that the storm which hit the mountain on May 10 last year was by no means exceptional.
The peak is regularly blasted by ferocious winds and the weather at high altitude can change with incredible speed.
Neither is it the case that only the weak and inexperienced die on high mountains.
Three experienced guides died on Everest during the storm.
In the past seven decades some of world's most gifted mountaineers have lost their lives tackling it.
One reason so many people died on Everest in May last year was simply that there were so many people.
Climbers were literally queuing up to use ropes on the high sections of the peak and several other expeditions were patiently awaiting their turn at Base Camp.
The simple truth that emerges from this sobering and thoughtful book is that all climbers at high altitude take their lives in their hands, and no amount of expertise, technology, and guiding will save you if conditions get rough.
In his introduction, Krakauer writes that many people advised him not to write this book so soon after last year's events.
He admits to having been traumatised by what happened and his friends thought little could be gained by opening his wounds before they had fully healed.
Krakauer resisted that advice, though, and as a result has produced a raw, brutally honest and more disturbing book, with none of the pat answers and comforting explanations he might later have formulated to make sense of the disaster on Everest.
Clearly it is a book that has touched chords in many people, having become a bestseller in Britain and the United States.
Some climbers have dubbed the southwest route to the top of the mountain - the one used by most expeditions and guided groups - the Yak Route. Ladders and ropes are laid along the way to help wealthy clients get to the top.
But Krakauer's book should serve as a grim warning to those who underestimate the savage and unpredictable powers of Nature: there is no easy way to the top of the roof of the world.
Into Thin Air by Jon Krakauer Villard, $250