Mount Index, South-North Traverse of the Three Peaks. The traverse of the three peaks of Index was a project that had for some time interested me. This traverse had been done only once before, when in 1951 it had been made from north to south. In early July, I was off from the car below Lake Serene at 10 a.m. The way to the summit of the South Peak, the highest of the three, is an easy but long scramble on the east and south sides through brush that is enough to test anybody’s perseverance. After a long climb with the last 250 feet of exhilarating grade IV, I was surprised to find myself on the summit of a peak which did not even boast a cairn several miles south of the true South Peak, to which ran a jagged ridge. I traversed on the west side until I reached easy slopes that led to the true top. The north face of the South Peak is a very complicated network of ridges and gullies, where difficulties would begin. Four rappels on a 300-foot rope, plus some descent on foot, brought me to a bivouac site. Early the next morning I made a final rappel into the notch between the South and Middle Peaks. The climb up the south face of the Middle Peak was not difficult but proved to be only the third ascent of that peak and the first via this route. It was here that I ran out of water, which was serious for this was the hottest day of the year and temperatures even at 5000 feet rose to over 80°. The descent of the north face of the Middle Peak was interesting, as after the last of my three rappels I found that I was 150 feet horizontally east of the notch between the North and Middle Peaks and separated from it by a very steep and exposed wall. Rather than to retreat and start over again, I made a grade —V traverse to the notch. The climb of the North Peak, previously unclimbed from the south notch, was the most difficult part of the entire traverse. The ridge crest was avoided by climbing below and on the east side for 200 feet; then the route continued for 300 feet on the west side. This was mostly grade IV or more difficult. An overhang where it was necessary to chin on branches was the crux pitch. Above this I ascended a subsidiary spur which drops down the west face to a notch where I had to master an extremely exposed and overhanging pitch (—VI). Another 150 feet brought me to the top of the North Peak, where I felt near exhaustion from lack of water. I stopped for an hour 300 feet below the summit on the descent to eat snow, and feeling somewhat refreshed, continued the descent via the very intricate regular route, which made me draw on all my route-finding experience to find the way down the unfamiliar 2500-foot face. The brush and scrub fir are so thick in places that it is impossible to see where you are going, or even where you are. Twice I had to reascend 300 feet to regain the route ; setting rappels was especially tiring. Just as I thought I was going to spend another night on the mountain, I discovered the way down the last 400 feet and stepped off the North Peak 31 hours after leaving the car.