Honnold doesn’t like this kind of talk; he insists that he worked hard to develop his self-control, and he grows prickly at any suggestion that he is unlike other people. “Before Dean solos something, he has to, like, slaughter a goat and fly with the ravens,” Honnold joked, as if Potter drew on magical aid to see him through danger. “I don’t want to slaughter a goat and fly with the ravens. I just want to climb.”

At Berkeley, I watched Honnold scramble out of sight onto the library roof. I heard him talking to somebody, and then he free-soloed all that long way back to the ground. He said a man had popped his head out of a window and said: “Don’t do that! Get down! These are offices, and you’re going to scare the librarians!”

Then a younger man appeared with a walkie-talkie. He said to Honnold: “You can’t do that here. If you’re going to do that, go somewhere else, O.K.?” Chastened and blushing again, Honnold walked away.

In November, Clif Bar, a major sponsor of Honnold and Potter, said it would no longer support them because of discomfort with their extreme risk-taking. Honnold responded with an Op-Ed article in this newspaper, accepting the company’s decision but declaring his intention to keep free-soloing. “If I have a particular gift, it’s a mental one,” he wrote. “The ability to keep it together where others might freak out. . . . Whether or not we’re sponsored, the mountains are calling, and we must go.”

Two months later, Tommy Caldwell’s Dawn Wall free-climb — in which he was roped up and securely protected, risk kept to a bare minimum — received international media attention and was widely hailed as the hardest rock climb ever done. I spoke to Honnold by telephone shortly afterward and asked how he thought about his free-soloing heroes nowadays. Honnold pointed out that Bachar, the original Yosemite free-soloist, remained bitterly committed to purist forms of climbing, even after he fathered a son. Bachar free-soloed until 2009, when he fell to his death from an easy climb near his home in Mammoth Lakes, Calif. Honnold claimed to feel much greater admiration for Peter Croft, “a happily married man” whose “eyes still light up like a child’s when he talks about climbing,” although he does it mostly with ropes these days.

But when I called Honnold on another occasion, he was lying in the meadow below El Capitan, looking up. “I feel kind of directionless,” he said. “Like, what’s my Dawn Wall?” I asked if a free-solo of El Capitan was still on his mind. Honnold admitted that it was the final unclimbed item on his private shortlist of dream free-solos. In 2013, he spent eight days at El Sendero Luminoso, in the desert of northern Mexico, dangling from ropes, memorizing hundreds of discrete movement sequences on tiny holds, before free-soloing it in January last year. This winter, Honnold free-soloed the second route on his list: Romantic Warrior, a 1,000-foot climb up a remote cliff in the southern Sierra Nevada, which had been free-soloed only once, in 2005, by a climber named Michael Reardon, who died two years later when he climbed without ropes down an Irish sea cliff and was swept away by a wave. The third challenge was University Wall, a notoriously difficult climb just north of Vancouver, a route that Peter Croft was the first to free-climb but never climbed without a rope. A young, up-and-coming free-soloist named Marc-Andre Leclerc, who lives near University Wall, was getting good enough to free-solo it. Honnold, who had been eyeing it for years, seized that prize for himself on his most recent trip last August.

But El Capitan is substantially bigger than any of these climbs, and it presents unique logistical challenges. The hardest part is 2,000 feet up, in a feature known as the Teflon Corner. “Anything called the Teflon Corner is not sweet for free-soloing,” Honnold said. He told me that he would consider an El Capitan free-solo only in the autumn, when the summer heat fades, the rock cools and Teflon Corner becomes less slippery. But the days are short then, and Honnold would still want to climb the Teflon Corner before the sun hit it; that would require starting well before dawn and free-soloing perhaps a thousand feet in the dark. If he decided to do it, he would need to spend days or even weeks roped up, climbing the Teflon Corner dozens of times in advance, mastering every move. Meanwhile, the world would be watching. “That would be so much pressure,” he told me. “All my friends would be texting me, like: ‘What are you doing? Don’t be stupid!’ Then some random guy would see me in the grocery store and be like, ‘When are you going to free-solo it?’ ”