HE HAS NOT BEEN inside, officially, for almost six years. He has not let himself be seen in public since November 10, 2001, when he gave a speech at a meeting of tribal leaders in Jalalabad, Afghanistan. In 2003, an Iranian source said that he had been seen arriving at a house for guests of the Iranian Revolutionary Guard in a small town west of Tehran. A spokesman for the Iranian foreign ministry vehemently denied this, calling the purported sighting "a fantasy." Informed speculation places him farther east, in the mountains along the border between Afghanistan and Pakistan. These mountains are a continuation of the Himalayas, a jumbled geological crash site caused by India running into Asia. Most ways through this near-wilderness have been made only by the feet of humans and pack animals. Here he and his companions probably live in a cave, or caves. For security, they may move often and at night. Very likely, he has been somewhere in these mountains all or most of the time since he left his last known residence, a house outside the Afghan city of Kandahar, on September 10, 2001. Whatever else you can say about him, by now Osama bin Laden, if he's still alive, is the ultimate outdoor guy in the world.

For the rigors of this demanding life he has been fortified by his piety and the expectation of heaven. In the past he has said that one day of fighting in Afghanistan is the equivalent of a thousand days praying in a mosque. A former bodyguard has said that bin Laden can live on nothing more than bread, dates, and water. His off-road vehicle of choice is a black Toyota Land Cruiser with dark-tinted windows. But aside from tales of his asceticism and a few incidental details, information about his outdoor existence these past six years is hard to come by. What, for example, is he doing for drinking water? Rivers in these mountains carry 20 times more water in summer than in winter because of glacial runoff; in the winter he must melt snow, but in summer, does he strain out the glacial scourings with a water filter? Everyone who's been in Afghanistan mentions the dust. How is he keeping it out of his computers and fax machine and satellite TV system and video camera, those fragile products of Western technology he loves and uses skillfully in jihad? Does he carry them in Hefty bags? The wind in these mountains howls in summer as well as winter; what does he do about chapping? And for some reason, I particularly wonder what kind of boots he wears.

When I find photos of bin Laden, I go over them almost pixel by pixel looking for clues. His standard working attire is a waist-length camo jacket of green, black, and brown—an out-of-place jungle color scheme, not like our own military's desert tans. (The garment may be partly ceremonial as well as functional.) Under the jacket he wears a shalwar kameez, a knee-length traditional long shirt, off-white, slit a foot or two up from the bottom on both sides, with loose trousers of the same material. His turban is white, and one end of it drapes over his left shoulder almost to his waist; perhaps when he needs to, he wraps that trailing end across his face against the dust. In winter pictures, he has geared up for the cold with a blanket, no doubt wool, of a light reddish purple color, which is thrown around the shoulders and hangs down to below the knee.

The question of his boots remains a mystery. Most photos of him are not full length, or else he's sitting or crouching in such a way that his feet are hidden under his robes. In a full-length photo I found, his footwear is just barely visible at the bottom. But in one of those swerves reality likes to pull, what he has on his feet appears to be carpet slippers.

They are shaggy and bright blue.