In 1905 Charles Howard Bury stained his skin with walnut juice and in disguise slipped into Tibet, crossing the high passes that led to Kailash. He later travelled to the Pamirs and Russian Turkestan, Kashmir and the Karakorum. Drawn always to the sacred, he read the works of Krishnamuriti and Kahlil Gibran, and visited in his many journeys theBuddhist monks of Angkor Wat, the high priests and shrine guardians of China, the mystics of Tibet. In India he embarked on a pilgrimage along the waters of the Ganges, anointing his body with scented oils to receive the teachings of the Sanskrit scholar Rewal at Badrinath. In one holy city, his reputation was made when he shot and killed a man-eating tiger that had carried off and eaten 21 fakirs, or holy men.

He was brilliant writer and an accomplished naturalist; he was fluent in 27 Asian and European languages.

In 1913 Bury spent six months exploring the Tien Shan, the Mountains of Heaven. In a local market, he bought a baby bear, which he named Agu. He nursed and protected the cub throughout his expedition, carrying it with him on his horse, and eventually bringing it home to Belvedere, his beloved estate in Ireland. Agu grew to seven feet and lived out its life in the arboretum. Wrestling with a mature bear from the Tien Shan would be, for Bury, his favourite form of exercise.

Bury fought throughout the first world war, until captured in the spring offensive of 1918. Statistically it was a miracle that he survived. At the Somme he nearly went mad. Ordered to cut a communication trench to Devil's Wood, he and his men had to dig not through the chalk soils of Picardy, but through great mounds of corpses, the dead of both sides, "heads, arms and legs crawling with maggots".

In 1921, leading the Everest Reconnaissance, he came upon a pilgrim 11 months out of Lhasa, moving 650 miles toward Kathmandu, one body length at a time in ritual prostration. For Bury, recently removed from the horror of Flanders, it was a stunning affirmation of religious purpose. He rode slowly past the man and listened. As his pony clip clopped along the track, he could hear over his shoulder the rustle of woollen cloth and the sound of hands passing over the dirt. To the south all of the peaks came clear and the snows of Everest could be seen looming against a lapis sky. The expedition reached its goal, the town of Tingri, just after noon on 19 June, exactlyone month and 362 miles after leaving Darjeeling.

Bury was a man of discretion and decorum, typical of a generation of men unprepared to yield their feelings to analysis, and quite unwilling to litter the world with themselves. Individuals so confident in their masculinity that they could speak of love between men without shame, collect butterflies and flowers in the dawn, paint watercolours in late morning, discuss poetry in the early afternoon and at dusk still be prepared to assault the German trenches or the flanks of the highest mountain in the world.

Wade Davis's Into the Silence (Vintage) won the 2012 Samuel Johnson prize.