The solitary ascent of the Dru had the immediate effect of expanding the horizons of my ideas about mountaineering. It made me aware of possibilities well in advance of the times, which were characterized by very restricted methods. This was how the superb pyramid of K2 surfaced once more in the list of my projects. But I chose K2 as a way for giving concrete form to my new concept of mountaineering: to climb the second highest mountain in the world solo, alpine style, and without oxygen.