I HIKED PARTWAY OUT with Geoff when he decamped for Bhutan. "That's probably the last hard Himalayan peak I'll be on," he said, looking back up at Cholatse's southwest ridge. You could see the faint line of his tracks bisecting a snowfield high on the mountain.

"God," he said, "we were so close, weren't we?"

When it was time for me to turn back, we stopped and hugged awkwardly around our backpacks. He seemed genuinely sorry to go. The part of his life spent climbing difficult mountains was over, replaced by his medical career and his family—not a bad transition, but a transition nonetheless. For a moment, as though he were experiencing a brief power outage, Geoff stood motionless. A lammergeier, a massive Himalayan raptor, floated on a thermal. The day was crisp and clear, the ragged white skyline of peaks thrusting into the clear sky. A gust blew hard along the hillside, kicking up dust. Then Geoff starting talking buoyantly again.

"Hey, did you hear the one about the monk who found a mistake in the sacred Buddhist scrolls?"

I shook my head, and Geoff launched into a joke on the famed celibacy of those cloistered disciples.

"So the monk goes to the rinpoche, an old man who's devoted all the days of his life to the monastic pursuit of wisdom, and he says, ‘Rinpoche, monks have been copying the texts by hand for nine centuries. We are worried that errors may have occurred.'

" 'Impossible!' says the rinpoche. ‘But I will check the original scrolls myself.'

"The next day the monk returns to find the old master with his head in his hands, sobbing. ‘Rinpoche, what is wrong?'

" ‘You were right,' the master tells the acolyte. ‘I have found an error. It says, "Celebrate"! "Celebrate"!' "

It took me a second, but then we both burst out laughing. Geoff turned and started hopping down the trail, tossing his hand up in a wave, moving fast to catch up with his two young porters. Then he rounded a bend and was gone.