Two hours into the approach, Pierce tells his group to take a rest. While they swat flies, he pulls out a photo he keeps in a Zip-loc bag and shows it to me. "This is Tammy and me on Rainier a couple weeks ago," he says. "The hoarfrost was amazing up there." He talks often about easing off the international circuit, and here is one of the key reasons: Full-time guiding is a notoriously efficient way to lose girlfriends. Things are great with Tammy now, but she won't put up with the world-traveler gig forever. The absences wear on Pierce, too. "You have to bring photos, man," he says, tucking away the picture. "Keep the morale up. You're out so much."

An hour later, Pierce and his clients break for water at a meadow just above tree line and get their first full view of Baker's steep, rough-cut north face. The afternoon sun casts deep shadows into a rutted arm of the Coleman Glacier flowing down a vertical mile from the summit. A slight breeze kicks up, wicking the sweat from their arms and bringing with it the sweet smell of subalpine firs. "There are moments when the stars align," Pierce will say later, recalling that pristine afternoon on the mountain. "It's a blue day, your clients are summiting, the view is stunning. That's when I can't see myself doing anything else."

Guides crave those blue days, but trouble comes nearly as often, and it only stands to reason that caution and a religious devotion to proper limits are hallmarks of the trade. Any guide will tell you: Good guiding and great climbing are mutually exclusive. The trade drills prudence into its practitioners because those without it do not survive. (Or their reputations don't survive the deaths of clients.) The two most famous mountaineering guides in the world—Rob Hall and Scott Fischer—became famous only after their deaths, and their colleagues continue to mull over the miscalculations they made on Everest in May 1996. Pierce thinks about disaster every time he goes out. He hasn't lost anyone yet, but the possibility keeps him on edge. "You can never become complacent," he says. "You've got to understand: On a bad day, people die on our job."

When it happens, an accident can turn even a veteran into an ex-guide. "I've watched people who've guided for ten years quit after getting involved in a tragedy," says Peter Whittaker, the 41-year-old co-owner of RMI. "But to be a fully rounded guide, I think you have to live through a few rescues. Mountain guides can get pretty cocky, yet we all make mistakes. Experiencing an accident humbles you and gives you an appreciation of how things can go wrong."

Whittaker knows. The son of RMI founder Lou Whittaker, he started guiding when he was 16 and went on to survive the worst mountaineering accident in American history, the 1981 icefall on Rainier that swept away ten climbers and another RMI guide. "I was 22," he recalls, "and lost all four clients on my rope." (Whittaker had clipped out just before the icefall occurred.) After helping with the official inquiry, he and a friend drove south and spent three weeks on the Colorado River. "I had to get my head together," he says. "We had a handful of guides who stopped after that season. They said, 'Eleven people. Jeez, I'm outta here.' But I'd grown up on Mount Rainier. I loved the mountains. I thought, 'There must be a reason I was spared.' So I continued guiding and used everything I learned to prevent other accidents."

The old alpinists called such guides "safe men." It still holds. "There's a fine line between helping people do these things they never imagined they could do, and doing it safely," says Burleson. "The best guides have tremendous foresight: They're always preventing an accident. It's all about prevention. Because once it happens, you're screwed."