Spy on the Roof of the World by Sydney Wignall (2000)

A True Story of Espionage and Survival in the Himalayas.

In 1955, Sydney Wignall, a Welshman climber, was recruited by Indian intelligence to report on Chinese military installations in Tibet and remote Himalayan border regions. After completing a long trek into rarely-visited regions, Wignall and his compatriots ere captured and imprisoned by the Chinese, who accused him of spying (correctly) for the CIA (incorrectly).

The trio were interrogated for months, during which time Wignall told the Chinese that the 1953 British expedition had planted a surveillance device on top of Everest - a piece of information he believes instigated the 1960 Chinese expedition to Everest.

Eventually, under international pressure, the captives were released - but they were forced to return on foot over the Seti Gorge, a dangerous pass where they faced slim odds of survival.

Paperback, 267 pages with a small insert of b&w photographs.