Considering the size of our group-19 of us, including five Ethiopian staff-a departure that early was going to be a stretch. With six more people and two more boats than Scaturro initially had planned, we weren't what you'd call fast-and-light. Our camps looked like deluxe Colorado River bivouacs, and the front storage bin of our booze barge, a classic old 18-foot Avon Spirit, was filled to the brim with clanking bottles, mostly local beer but also wine, whiskey, and a deadly off-brand ouzo. After a delirious party one night upriver, there had been so many empties strewn around the fire pit that Scaturro had declared a moratorium on happy hour.

To be fair, our late departure wasn't entirely Petros's fault. But by then the pudgy, garrulous cultural anthropologist and tour guide had become everybody's favorite whipping boy. He'd sold himself to Scaturro on the strength of his academic credentials and purported expertise on the Omo Valley's tribes-the Bodi, Bumi, and Mursi, among others. That remained to be seen, since we hadn't come to any villages yet. But as a manager he'd already proven undependable. He'd arrived at the Bele Bridge, our first resupply spot, two days upriver, with plenty of food and cold beer but without the mounting hardware for an outboard motor that we'd need to power through the Lower Omo's sluggish meanders.

"We ain't going nowhere on the lower river without those pipes, Petros!" Scaturro had exploded. "How many times did I tell you, 'On penalty of death, don't forget those parts'? Jesus Christ! I said it 20 times and should have said it 21."

"I delegated this responsibility," Petros explained lamely. Scaturro stomped off, placed a satellite call to our outfitter, Red Jackal tours, and arranged to have the parts driven overnight to the next road access, about 20 miles downriver.

As a leader, Scaturro can be overbearing and foulmouthed, salting his orders with run-on profanities that would make a Soprano blush. In his view, an expedition team has one decider-in-chief-him-and when he bellows an order, you'd better jump. But he knows he's not infallible.

"My definition of a great team is one that continues to function when the leader goes down, like I did on Everest," he says. "The leader's role is to pick a team, train them, and then make himself irrelevant."

Despite his outbursts, he seems to thrive on fixing snafus and coaxing the best out of people. Between oil and gas gigs and what he calls his "high-profile" expeditions, he loves nothing more than bringing together comrades and casual acquaintances on a do-it-yourself adventure, for which everyone shares the cost. He's a pied piper to an ever-changing entourage of climbers, rafters, trekkers, and ordinary travelers who would follow him just about anywhere.

"He's a great team leader," says Mike Prosser, a bearish, gray-bearded river-equipment manufacturer who ran the upper Blue Nile with Scaturro and jumped at the invitation to row the Omo. "He can be demanding and he'll get in your face, but five minutes later he'll put his arm around you and it's over."

Twenty-five years ago, Scaturro considered guiding as a career but decided against taking passengers down the same rivers or up the same slopes again and again, like a glorified tour-bus operator. Instead, he sees his role as a catalyst, coach, and master of ceremonies. When we'd all met up in Addis Ababa a couple of weeks earlier, he'd assigned key tasks like rigging rafts to the boatmen and crew, while everyone else eagerly pitched in. On shopping excursions, he led the way into Addis's sprawling open-air market, the Mercato, ordering large quantities of provisions, dickering, and clearly relishing the role of tour leader and consummate Africa hand. At noisy team dinners, Scaturro was lord of the banquet to his adoring subjects, spinning stories about his trips on the Omo ("mud two feet deep in camp") and the Ogaden ("the asshole pulled the pin and held the grenade on our hood"). It probably wouldn't have mattered if they were in Addis or Anchorage, as long as they were with the man they knew as "PV," short for Pasquale Vincent.

"I've never met anyone with his energy and drive," says Steve Jones, one of our lead boatmen. Jones had logged nearly 90 trips down the Colorado as a commercial guide in the 1980s and later went to Chile with Scaturro to raft the Bío-Bío. "These expeditions are not fun a hundred percent of the time," he says. "The trips get long, people can get sick and irritable. Pasquale seems to have a larger appetite for these tough expeditions than anyone I know."

Our third raft was piloted by another of Scaturro's old friends, Kurt Hoppe, an ultrafit oil-exploration consultant who'd rowed part of the Blue Nile with him. For assistant boatmen, he'd tapped two young guys, Zach Gill and Zach Baird- "Big Zach and Pro Zach"-who were like sons to him. The rest of us looked like package tourists-a lawyer and her computer-scientist husband, a veterinarian, a software salesman, a marketing exec, and a business-school professor.

On the Nile expedition, Scaturro's Ethiopian staff had secretly called him chakwala, which in Amharic means something like "impatient and pushy." But two had agreed to be rehired: Yalew Mteku, his agile little factotum; and Baye Gebreselassie, our security guard, a laconic soldier who looks like Denzel Washington. Scaturro had also recruited Robel Petros, a seasoned crewman, and Tesomen Gesla, our cook.

After five days, we rolled out of Addis in an air-conditioned Mercedes coach followed by a cargo truck stuffed with rolled-up boats and gear, heading for the Great Rift Valley and the put-in bridge.

"God, I'm tired," Scaturro said. "I can't wait to get on the river."