FOUR DAYS LATER, I left the expedition, along with six others who had commitments at home. We found out by e-mail that the remaining team members had reached Lake Turkana, but there had been no trekking, no colonel, and no SPLA escort. Instead, they had waited three days at a riverside missionary station for a truck that Petros had insisted was coming, then had driven to a border outpost called Kibbish Wells. Petros had gotten sick and moaned that he was dying. Scaturro had slipped him a sleeping pill to shut him up.

After he got home, Scaturro e-mailed a final thank-you to everyone on the team. "I have never been with a commercial or private group in such difficult conditions and had such a wonderful time," he wrote.

"I know the trip I want to take now," Scaturro told me later. "I want to go back next year, take a dugout across the lower river, and start walking. It'll be a 400-kilometer walk. I'm convinced that if there are any authentic tribes left in Africa, we'll find them."

But that would have to wait. Last July, Scaturro flew to Pakistan to join the Shared Summits Expedition on K2. In September, he led a team down Ethiopia's Tekeze, portaging around a dam that will choke off that river. He ended 2007 in the Middle East, working with a television crew producing a series on the Arab countries.

Meanwhile, his wish list is ever-expanding: Raft the Mekong from source to sea, walk the length of Russia's Kamchatka Peninsula, sail the South Pacific, drive from Cape Town to Lon­don. He and Weihenmayer are talking about putting up a new route on New Guinea's Carstensz Pyramid, one of the Seven Summits.

"I'm not afraid of dying," Scaturro says. "I'm afraid of dying before I do everything I want to do. People always ask me, 'How do you do it, and how can I do it?' I tell them that we've been born into the greatest country on earth. All we have to do is to get rid of our fear and control the guilt-family guilt, church guilt, work guilt-and take advantage of the opportunity. When I hear, 'I can't go, my grass will die,' I say, 'Tear out the grass and let's go adventuring.'

"Because in the end, it's all about friends and memories, baby."