What is the author's tone in The White Spider: The Story of the North Face of the Eiger by Heinrich Harrer?

In The White Spider, Heinrich Harrer exhibits somewhat of a nostalgic tone. Harrer's experience in climbing the North Face of the Eiger was life-changing, even if he didn't realize it at the time. The experience was one of his youth, and he associates mountain climbing with youthfulness, health, and freshness of mind and body. Harrer strongly feels the sublime nature of the mountain and admires the desire to become a part of it in exacting physical challenge. Describing the attempts, and particularly the most admirable ones, to climb the North Face seems to be, for Harrer, describing an ideal.