Half Dome is the symbol of Yosemite National Park, a world-famous rock formation with a towering summit over Yosemite Valley and sheer walls on all sides. Dirk and myself successfully climbed its Snake Dike route on June 11-12, 2005. The Snake Dike route has a difficulty rating of 5.7 R, and is the easiest route to the summit other than the standard cable route. We planned to use the cable route for descent, even though the latest word was that the cables had not yet been set up for the season (this means the steel cables would be lying on the ground, not supported by posts). The Snake Dike route has a letter "R" (run-out) in its rating because the entire route is free of cracks, so that protection devices for technical climbing (called "pros") could not be inserted. Climbers have to rely entirely on fixed anchors which can be very far away from each other. These technical difficulties pose challenges for primarily the leader climber (that would be Dirk), but the climbing is reputedly superb with lots of face and slab climbing on lower-angle knobby granite. We planned to complete the climb within one day, so no wilderness permit would be needed. Although it would make a long, exhausting day (vertical elevation gain is 5000+ feet, trail length is 14+ miles), it was doable and I looked forward to getting to the summit of Half Dome, situated smack in the center of the unique geologic wonderland of upper Yosemite Valley.We started hiking from Curry Village a little before sunrise, and proceeded up the usually popular mist trail. The raging waters of Merced River created spectacular sights at Vernal Fall and Nevada Fall, both of which were breath-taking. After the 2000-foot vertical gain to the top of Nevada Fall, there was another 1300 vertical feet of cross-country scrambling to get to the base of the climb, on the southwest side of the dome. Near the base of the dome, Dirk took a path up a steep, class 5 section of sloping granite slabs, and could not progress further. I took an easier way and made it about 20 feet above him already, so he called for me to help. The terrain was slippery and dangerous, so I took off my backpack, then stepped carefully over to lend him a hand. It helped. Later on, we had to go through some dense manzanita bush in order to get to the climb, and it seemed there was no way to avoid bush-whacking. Carrying the 60-meter rope I was exhausted from the 6-mile, 3400 vertical feet of the approach route. In the past I climbed whole mountains with this much effort, this time it was only the approach! It took 5 hours for us to complete this approach route. Right before the start of the technical climbing route we had to climb unroped up a steep slabby section, seemingly 5th class. Dirk later commented that this was harder than much of the route (but less exposed). Once at the start of the route we had to wait for 3 parties that were already climbing above us. We were able to start climbing after waiting for an hour, and the party below us had to abandon the climb after 2 pitches. As clouds were starting to build above us our anxiety about thunderstorms and lightning increased. Most of the climbing pitches were similar, where one follows a continuous knobby protrusion from the granite slope (i.e. the "Snake Dike") using hands and feet. The angle started at about 60 degrees and gradually lessened. In the 2nd pitch there was a 20 feet unprotected traverse that must have been spooky for Dirk, but as the follower I am much better protected by the rope and felt safe, although it still took some careful maneuvring. What bothered me a lot was that most of the belay stances were so poor that my toes were in pain constantly. The sloping rock face was no place to stand on comfortably, and being tethered to the fixed anchor assured safety but didn't alleviate the serious strain on my muscles. For the next 5 pitches, the climbing was easy but the lower the angle of the slope became, the more awkward my climbing stance became. The climbing was strenuous because hand holds were very low so one is constantly crouching and crawling. After the 6th pitch, it was getting late and more clouds were building overhead. Dirk suggested that we climb the next two pitches unroped. I resisted the idea but the fact that there were now cracks for hand and feet jamming made me feel much safer. The slope at this point was about 40 degrees, any slipping could be fatal as one slides down the slope with increasing steepness. I took advantage of the cracks to move myself up toward lower-angle slopes above me, but was stopped by chest-high step I have to climb over. I became afraid as the available hand holds were poor. Dirk came over and show me how to do it, basically shifting one's weight toward the front and crawling up the step, carefully. With his encouragement I overcame this obstacle. After this, it was more and more crawling over lower-angled slopes (25-40 degrees) for about 1000 vertical feet, near the end of which the slope became so flat it was possible to stand up and walk on it. The climb was mostly easy but long and strenuous; eventually I made it to the summit of Half Dome about 40 minutes after Dirk. There was another party of two climbers still on the summit, but they descended soon after. It was approaching sunset time and the sky was filled with dramatic clouds, covering the tops of many surrounding high peaks. The golden rays of the sun spilled over beautifully from in-between cloud formations. The views over the Tenaya and Merced canyons were simply majestic, especially with 4 big visible waterfalls below us, and much snow-covered terrain in higher elevations. Looking around the summit, the views are beyond breath-taking, especially down the sheer northwest face of Half Dome toward the void, far below which is Tenaya canyon and the huge void that is Yosemite Valley. I wished I could stay longer on the summit, maybe even camping there for a night. Dirk ventured onto the 20 feet long rock formation jutting out from the northwest face of Half Dome for a hero shot. Below him was more than a thousand feet of air. As it got darker we started the descent down the cables route. My fears were confirmed that the slope along the route was very steep (around 50 degrees on average), in fact as steep as parts of the technical climbing route we had just done. The steel cable that normally hikers use to hold on were lying on the smooth surface of the rock. In order to provide a degree of safety Dirk suggested that I use a carabiner to tie myself into the cable. This helped, as I could only slide down as far as the next anchor of the cable if I lost my grip. I pulled up the cable from the ground, which were very heavy, and walked down the steep slope carefully as I moved my grip downward. Every time I reached one of the anchors of the cable, I would switch my carabiner to the next segment of the cable. With this procedure I was able to descend to the base of the cables without problems. Dirk on the other hand, walked down the section without tethering himself to the cable. The hike down after this was long and uneventful. We were exhausted and plodded along the 8 miles. I decided to choose the regular John Muir Trail rather than the Mist Trail alternative, for fear of slipping hazards in the darkness of night. On a lower section of John Muir Trail I saw a pair of green eyes flashed in the darkness, then the animal jumped away. I thought it was a deer, but Dirk then had another encounter with it and figured that it was a mountain lion. This made him a little apprehensive, although mountain lions usually stay away from humans. Once inside Yosemite Valley when we thought we were almost done, we had trouble finding Curry Village, where my car was parked. This took us almost another hour, after talking with two patrolling rangers. We made it to the car around 2 am on Sunday morning, totally exhausted.