A new book chronicles the struggles of early climbers as they attempted to mount expeditions on the world’s highest peaks

In 1907, Tom Longstaff made the first known summit of a 7,000-plus-meter peak, Trisul in the Himalayas. What did he consider the sine qua non for a mountaineer? The answer may surprise you.

Longstaff believed that “the most important quality of a mountaineer” was “knowing when to turn back,” according to Dan Light, who documents the rise of mountaineering in the late 19th and early 20th centuries in a new book, The White Ladder: Triumph and Tragedy at the Dawn of Mountaineering.