It happened so quickly I didn't have time to be scared. One moment I was hopping onto a sloping ledge covered with loose rocks. The next I was pitching crazily forward, tumbling head over heels into a somersault. I landed on my back with a sickening cra-a-a-ack, and continued bouncing down the rocks.

"Grab something!" I told myself. I reached out but it was all happening too fast. My hands glanced off the rocks as the world cartwheeled wildly around me. I flipped over again and again, cracking my shoulder and my back on the rocks.

Everything seemed to be happening in slow motion, yet at the same time too quickly for me to react. I was helpless to stop myself; I kept sliding and bouncing down the gully, shredding my skin on the rough granite.

"This is it," I said to myself. "This is what it's like to die."

My head smacked into one rock outcrop; another caught me in the ribs. Then I was falling through the air, down a vertical headwall. I crashed into rocks at the bottom and kept tumbling and rolling down the steep mountainside.

I honestly don't know what stopped me. Certainly it was nothing I did. After about a hundred feet of bouncing like a pinball down the rocky chute, my body finally came to rest on a flat ledge. If I had missed it, I probably would have gone all the way to the bottom, another thousand feet below.

I lay there gasping for breath. My heart pounded as if it were going to burst out of my chest. I was in a world of hurt. My clothes were shredded, my body covered with gashes and gravel. Reaching slowly behind my head, I felt a sharp, jabbing pain exploded in my chest. I felt sick to my stomach, and chills racked my body.

The next thing I remember, Peter was by my side. "Hang tight," he said. "I'm going for help. It should be here first thing tomorrow." Suddenly he was gone and I was alone on the ledge. It was very quiet.

(Peter) Later that day we finally received word that Mark was alive, and that they had been able to fly him out. I felt utter relief. It was another day and a half before I would see him.

I tiptoed into the intensive care unit, where Mark was. He had tubes coming out of just about every bodily orifice. I asked him if he was doing alright, and I'll never forget what he said.

"Peter," he said weakly, "at last we climbed the peak."

At the time I thought it was a bit of misplaced bravado, I still think it was excessive, but that's the kind of attitude that got him through the night. And that's what allowed him to climb another mountain one day.

Summit fever filled my arms with energy, and I cranked off the last few hundred of my seven thousand chin-ups without even pausing to rest. We were so close we could almost smell the top. The severe angle of the wall eased off and Corbett found he could scramble up it without pounding in pitons every few feet. Standing on a small ledge, he turned his back to me and bent down.

"Hop aboard," he said.

So we'd finish El Capitan the way we started it, with me riding piggyback on Mike. We were still on dangerous terrain, but after the absolute sheer verticality of the last twenty-nine hundred feet, it seemed like a cakewalk.

I wrapped my arms around Corbett's neck and used a carabiner to attach my harness to his. After eight days on El Cap, his body felt bony. His movement were tentative and his legs seemed wobbly, like an astronaut returning to earth after a week in zero gravity. But after all we had been through together, I had complete and total confidence in him.

Mike moved slowly and with exaggerated care up the last steep section of the route, pausing every few feet to catch his breath. Suddenly, over our shoulders, there was an ear-splitting roar. I looked up to see a helicopter from one of the San Francisco television stations only five hundred feet above us, a cameraman leaning out the window. The pilot was flagrantly violating National Park regulations, which require aircraft to stay two thousand feet above the valley rim.

The angle eased further, and Corbett tried to pick up the pace. Now dispensing with the rope altogether, he fought a battle with impatience and exhaustion. The summit couldn't arrive soon enough for either of us.

We were moving up a sloping slap of granite covered with loose gravel when it happened.

Mike's foot slipped, his legs buckled slightly, and for one horrifying moment we teetered there, on the brink. An electric current of fear jolted me out of my weariness. The circumstances were frighteningly similar to those of seven years before, when a single instant of carelessness had changed my life forever. Then, as now, it had been a few pebbles out of an entire mountain that got me.

Corbett staggered, trying to regain his balance. I held my breath. If we lost it here, there would be nothing to stop us . . .