THREE HOURS AFTER RUSHING to the airport, we finally board a 12-seat twin-turboprop Beechcraft and lift off over the brown expanse of Kabul. The plane is operated by PACTEC, a nonprofit that shuttles humanitarian workers around Afghanistan. PACTEC offers no beverage service, but the seat pocket does contain a laminated guide to avoiding land mines, which still kill or maim around 65 Afghan civilians every month. As the Beechcraft arrows toward Badakhshan, Afghanistan's northeasternmost province, we gaze east toward the 19,000-foot peaks guarding the approaches to the Pakistani region of Baltistan, where Mortenson forged the ideas that define his mission. Ever since Islam was brought into the Baltistan area by itinerant Muslim sheiks in the 15th century, the privilege of learning to read and write has, in many mountain communities, been reserved for males. Like most experts, Mortenson is convinced that educating girls is the most important step in reducing infant mortality and bringing down birth rates—which in turn helps fight the ignorance and poverty that often nurture religious or ethnic intolerance. Thus every new school the CAI funds must provide access to girls.

"Once you educate the boys, they tend to leave the villages and search for work," says Mortenson, who spent most of his boyhood in East Africa, where his parents—Lutherans from Minnesota—built Tanzania's first teaching hospital, in the shadow of Kilimanjaro. "But the girls stay home, become leaders in the community, and pass on what they've learned. If you really want to improve quality of life, the answer is to empower the women by educating the girls." The importance of girls' education is widely recognized around the world. CAI's special twist is the amount of time and effort Mortenson spends selling the concept on the ground. His guiding philosophy is summed up in his book's title, which refers to a saying he heard in Korphe. "The first cup of tea you share with us, you are a stranger," it goes. "The second cup, you are a friend. But with the third cup, you become family—and for our families we are willing to do anything, even die."

"In order to get things done, it's necessary to listen with humility to what others are asking for and what they have to say," says Mortenson. "The solution to every problem over here begins with drinking tea."

This might sound simplistic, but the results are impossible to dispute. Down inside the narrow mountain valleys that lie veined far below the Beechcraft—where more than 400 villages are now clamoring for a school—the first crop of CAI-educated women are preparing to launch their careers. Jahan Ali, 21, the granddaughter of the headman of Korphe, graduated in 2002 and is studying developmental planning in Skardu. She plans to go into politics. Shakila Khan, 21, graduated with the first class in Hushe School and is finishing her third year of medical school in Lahore. She will be the first female physician to emerge from an area of the country that harbors 1.2 million people.

"You could say that those women down there are making first ascents far more dramatic than those of the Western climbers who came into these mountains 30 or 40 years ago," says Mortenson, who next March will receive the Sitara-e-Pakistan, Pakistan's highest civilian award, which is almost never given to a foreigner. "They will have a far greater impact than the statistics buried inside the pages of The American Alpine Journal."

True enough. And yet it was the sport of mountaineering—the strength of will it demands, the maverick impulses it can nurture and shape—that first inspired Mortenson's radically unorthodox approach to building schools. Pointing through the plane's window at the distant summit of Noshaq, at 24,581 feet the highest peak in Afghanistan, he explains the overall blueprint. "If you look at a map," he says, "you'll see that our schools are all in isolated pockets that have no educational infrastructure due to remoteness, poverty, religious extremism, or war. These are the areas where nobody else goes—and, basically, what we do is start at the end of the road and work our way back. We don't want to build thousands of schools. We just want to put a few into the hardest places of all, then hope that the government or other NGOs will start moving toward us."

The strategy has worked well in Pakistan, where Mortenson's staff spent the late nineties targeting the farthest-flung villages in the most remote valleys. In 1999, at the request of the Pakistani military, they launched projects in the Gultori region, where the armies of India and Pakistan were locked in fierce fighting along the Line of Control, which defines Kashmir's contested border. The schools they put in, which were tucked into the mouths of caves, featured sloped roofs that can deflect rockslides triggered by artillery shells. That fall, they also started working with contacts in Afghanistan—an effort spearheaded by the broken-handed man now sitting in the back of the Beechcraft, whom Mortenson likes to call "our Indiana Jones."

This is Sarfraz Khan, 53, who was shot through the wrist during a gun battle with the Indian army in 1974. After his military discharge, Sarfraz started plying the snow- covered passes that connect his home in Pakistan's Chapursan Valley to the Wakhan Corridor, a narrow finger of Afghanistan, 200 miles long, that thrusts between Tajikistan and Pakistan all the way to China. Three or four times a year, Sarfraz would haul flour, sugar, and tea into the Wakhan—an area almost completely cut off from the outside world—and return with yaks and goats. The work helped create a unique skill set: He knew the terrain; he knew the people along the border; and he had a superb grasp of the local languages—all seven of them.

Mortenson met Sarfraz in 1999 and, the next year, dispatched him to survey the Wakhan's infrastructure. Sarfraz found that after nearly three decades of war, there was barely a skilled mason or carpenter left in the corridor. His solution was to import teams of Pakistani craftsmen. With permission from the border police, he started escorting groups of 20 workers at a time over the passes without visas or passports. Every few weeks, he would return to monitor progress and pay the men with money he carried in saddlebags. He set such a relentless pace that at the end of one trip, upon reaching the far side of the pass, his horse fell to the ground and died.

By the summer of 2008, the CAI had built nine Wakhan schools, with five more in the works. Our current visit will include a typical mix of ribbon-cutting ceremonies, bill paying, and meetings to discuss new projects. The plan is to land in the provincial capital of Faizabad, then head east until we reach the end of the road, at the village of Sarhad.

That's the scheduled itinerary, anyway. With Mortenson, there are always surprises, and the first arrives as our plane taxis to a stop and the copilot turns to face the passengers. "Welcome to Badakhshan," he announces. "Whichever one of you guys has got the armed escort, they're headed this way."