By the time I saw the wall of water burst from behind the boulder to my left, it was too late. I was tossed like a toothpick into Idaho's Main Salmon River.

Sputtering in the powerful current, I held onto the paddle and the inflatable kayak I'd tipped until I landed on a shallow gravel bed. With the insistent river tugging on my legs, I flipped the kayak, crawled in and paddled to the peaceful cove where the river guides and my party awaited.

"Nice self-rescue, Jim," said one of our crew of five guides. Others, including my wife and friends, weren't as kind. They just laughed. The guide had, after all, warned the other river guides to steer their 16-foot rafts clear of the ledge that had tripped me up while negotiating the day's last set of rapids.

Swallowing river water along with humble pie was a cheap lesson on a trip that otherwise offered a safe river float peppered with excitement, stunning scenery, engaging company — and a growing respect for the river. The Salmon River doesn't care if you spill or chill while on its course. It does demand, however, that you navigate its currents on its own terms.

Those terms are simple — this is a wild, undammed river. Flowing 425 miles within Idaho, the Salmon drops from elevations above 8,000 feet in the Sawtooth Mountains to 905 feet at its confluence with the Snake River near the Idaho-Oregon border. It is the longest free-flowing river in the Lower 48 states, cascading through national forests and two wilderness areas, including the Frank Church River of No Return Wilderness, the country's second-largest wilderness area in the Lower 48. The river slices through the second-deepest gorge on the continent (Hells Canyon on the Snake River is the deepest). The Salmon's granite-walled canyon, more than 1,000 feet deeper than the Grand Canyon, cuts more than a mile into the Earth for about 180 miles.

The Salmon River Canyon, unlike the sheer walls of the Grand Canyon, offers a variety of landscapes visible from water level: wooded ridges climbing to the sky, solitary crags and photogenic castles, towers and slides. When you can take your eyes off the river, you might spot a nimble bighorn sheep on the pine-studded canyon walls or a golden eagle coasting in the updrafts overhead.

The lyrical moniker, the River of No Return, has its origin in the realities of early Salmon River travel: You could float down, but it was darned near impossible to climb back up the fast-flowing waters. Today, jet boats take care of that problem. For more than a century after the first European Americans arrived, though, river journeys were strictly one-way. Wooden scows, carrying heavy loads and able to weather the white water, did the job. At the end of the odyssey, the scows were dismantled and used for lumber.

Returning home was the last thing on my mind as my group of six Minnesotans pulled into Salmon, Idaho. Salmon is a bustling river town of 3,100 nestled in the shadow of the Bitterroot Range, to the east. Our group, along with 13 other trip mates, met with Alison Steen, owner of Yellow Jacket River Guides, for our orientation meeting the evening before our put-in. Alison's roots run deep in this country; her great-grandfather staked a gold claim near here in the 1870s in the present-day ghost town of Yellow Jacket.

Her company is one of about 30 licensed outfitters that serve visitors on the Main Salmon River, each one stocked with professional guides and gourmet food. Families are welcome and are in for a rare treat — a safe, thrilling wilderness river float trip in relative comfort.

Alison gave each of us a large waterproof night bag, a small day bag and an ammo case for sunglasses, sunscreen and other small items we would want close at hand. With gear loaded on the bus the next morning, 19 enthusiastic group members chatted, joked and daydreamed during the two-hour drive to the Corn Creek Landing, at the end of a dirt access road.

The bus driver pointed out Lewis and Clark's farthest river advance on the Salmon. This was the place where the Corps of Discovery discovered that they could not safely navigate the Salmon, so they headed farther north to find an alternative route to the Pacific.

After meeting our five guides for the four-night, five-day adventure, we ate a picnic lunch along the banks of the Salmon. The guides directed traffic as we pitched in to get our gear loaded and secured on the waiting rafts. Since we were entering the Frank Church River of No Return Wilderness area, we listened to a U.S. Forest Service ranger discuss "Leave No Trace" camping in the wilderness, which involves sealed portable toilets and packing out garbage to preserve the wildlands — and make the next group's trip as pleasant as ours.

Because our group was bigger than usual, some of our guides were employed by other outfitters. The outfitters also share gear with one another when needed, adding to an atmosphere of professional courtesy on the river.

On the water, we had three choices for rides. There were three 16-foot, self-bailing, oar-powered rafts, which a guide controlled with two large oars. A smaller 14-foot paddle raft required its four to six passengers to paddle while a guide steered. The guides had also brought two inflatable kayaks (single- and double-seat craft) for anyone who wanted to try their luck. A fifth guide handled a sweep raft, which carried all of the camping gear.

The Salmon is a "pool and drop" river, meaning that at the end of each rapid is a slow-moving pool of water inviting you to jump in for a swim. With daytime air temperatures between 85 and 95 degrees and the cool river, water wars were bound to break out.

Between splashes in the pools, the guides pointed out geologic highlights and told river tales. We would beach at times for short hikes that led to glimpses of the region's past: historic sites of early Nez Percé and Shoshone Indian settlement as well as abandoned homesteads, cabins and mines. One stop involved an uphill scramble to reach Barth Hot Springs, where we took turns basking in the soothing water. Another took us to the Buckskin Bill Museum, the preserved home of the river hermit known for living off the land and making his own clothing with deerskin. At Campbell's Ferry Pack Bridge, we learned about old-time prospector and local character Jim Moore.

At challenging rapids, our floating caravan paused to plan our approach. The guides had good river maps and experience on the Salmon. Yet they would sometimes scout on foot from the riverbank to plan the best route and avoid dangerous obstacles. As much fun as they had joining in the calm water fun, they were all business on the white water. The Salmon is famous for its Class III rapids, with names like Salmon Falls, Split Rock and Whiplash. Our guides had to sometimes make complex maneuvers in fast current, requiring good raft control in the tight passages or around ledges.

The rapids are big and exhilarating. As I watched from below the rapids, I'd see an oar boat dip into a "hole" with only the guide's head visible. Then the raft would explode up through a wall of water, drenching my laughing tripmates.

On the paddle boat, our guide encouraged us to take turns sitting on the bow, hanging onto the boat while she shouted paddling instructions to the other four. This was like riding a bronco through the rapids. Sometimes a wave would knock one of us off balance, shooting our feet in the air while our arms — and those of other rafters — pulled us back in.

We could switch watercraft at any time. Some preferred to ride one of the oar boats and let the guide handle the raft while lying back in the sun. The oar boats were favorites of families with young children or for any apprehensive rafters. The kayaks were popular and in use most days. Our group of six preferred the paddle boat where we could work on the rapids and play on the pools.

The guides were as professional and fun in camp as they were on the river. Three of the four nights our group camped on beautiful white sand beaches. While the guides prepared hors d'oeuvres and gourmet meals, we hiked, swam, fished, read or enjoyed a cocktail or hot drink by the campfire. The guides brought along tents for those who wanted one. Most of us chose to sleep on the beach, laying our sleeping bags on pads while falling asleep under the stars. Coming from Minnesota, we marveled at the lack of mosquitoes.

On the third night, we beached at China Bar Lodge. Hot showers, beds and a ranch-style dinner and breakfast awaited us. Later, we sat around the beach campfire while the lodge owner and two guides played guitar and sang. It was a pleasant accompaniment to the music of the river with the starry vault stretching overhead.

The last full day was a hot, long paddle of 22 miles on mostly quiet water. After an evening meal of steak, asparagus and potatoes, it was time for the Olympics. Organized by the guides, we played bocce ball and Hunker Down — a tug of war between two people standing on ammo cases. The highlight was sumo wrestling while wrapped in sleeping pads. By the time the campfire embers ebbed, most of us had filtered off to bed.

The next dawn meant rigging the boats for the last time and a 12-mile paddle to Carey Creek Boat Landing, our takeout point..

With a raft of memories and sand everywhere, we rode the bus with our new friends to Riggins. For us, the River of No Return is definitely worth a return trip.

Jim Umhoefer is an outdoor travel writer and photographer from Sauk Centre, Minn.