Most young people enjoy some form of physical activity. It might be walking, cycling or swimming, or in winter, skating or skiing. It might be a game of some kind like football, hockey, golf or tennis, or it might be mountaineering. Those who have a passion for climbing high and difficult mountain are often looked upon with astonishment. Why are men and women willing to suffer cold and hardship, and to take risks on high mountains? This astonishment is probably caused by the difference between mountaineering and other forms of activity to which men give their leisure. If we compare mountaineering and other more familiar sports, we might think that one big difference is that mountaineering is not a "team sport". We should be mistaken in this. There are, it is true, no "matches" between "teams" of climbers. However, when climbers are on a rock face linked by a rope on which their lives may depend, there is obviously teamwork.