The legendary partnership of Eric Shipton and H W Tilman is unique in the history of 20th-century mountaineering. They met for the first time early in 1930 in Kenya, where both were working on coffee plantations: ‘a good life’, Shipton wrote, ‘full of interest and variety, and … a great sense of freedom’.

At this stage, Tilman’s brief climbing experience was confined to the Lake District, while Shipton had climbed in the Swiss Alps, the Bergeller, England, France and Wales. Having rejected a career in law, Shipton’s degree in estate management led to Africa. With Gustav Sommerfelt and Percy Wyn Harris, he climbed the twin peaks of Mount Kenya in 1929, the first successful ascent since Halford Mackinder’s pioneering venture thirty years earlier.

In 1930, Shipton and Tilman climbed Mount Kenya’s formidable west ridge. It was a splendid achievement, especially for Tilman, a veteran of the Great War, nine years older than Shipton and still a novice. Jim Perrin rightly insists that the complex psychology of a climbing partnership, like marriage, is based