Dawn in the South Pacific. The night has been squally, but the weather is clearing, as it usually does at this hour in this part of the world. The landing is still some hours away, but many on the ship are already up and about, walking thoughtfully along the weatherdecks or talking quietly in small groups.

Excitement and anticipation mount as the landing is discussed. Little is known about the tides and beach gradient. The sea has been choppy, the wind rising for the last few hours. A note of concern creeps into the conversation. Will the landing craft make it ashore, or will the landing party have to wade? Will a landing be possible at all? The next few hours will tell.

"Guadalcanal Diary"? "Sands of Iwo Jima"? World War II novel? No -- it's a tour of the South Pacific aboard the luxury Greek cruise ship Illiria. The Illiria, on its 11-day trip through the not-so-sunny South Pacific (some areas receive an average of 20 days of rain during certain months), will stop at such unconventional vacation spots as the Trobriand Islands, Bougainville, Guadalcanal, the Santa Cruz Islands and Vanuatu (formerly the New Hebrides). These islands once formed part of Gen. Douglas MacArthur's Southwest Pacific Theater and Adm. William F. Halsey's South Pacific Theater.

The Illiria's itinerary is a compromise between historical and scientific interests and depends on many factors -- the ship's schedule, the weather and the availability of good anchorages and harbors. On this early spring trip, sponsored by the Smithsonian Resident Associates, the Illiria will be sailing southeast from Rabaul on New Britain Island in the Bismarck Archipelago, down through the Solomons to Guadalcanal and into the Santa Cruz Islands and Vanuatu. (In World War II the United States and its allies first captured Guadalcanal, then advanced northwest "up the ladder of the Solomons" toward New Britain. The object of all these campaigns -- in the later stages they received the collective code name CARTWHEEL -- was to isolate and destroy the great Japanese air and naval base at Rabaul.)

To make things a little more complicated, the cruise actually begins in Port Moresby, in Papua New Guinea, which served as the staging area for yet another set of campaigns under Gen. MacArthur that were intended to dislodge the Japanese from the north coast of the Papuan peninsula.

As historian for the trip, I attempt to explain all this during my first lecture in the ship's elegant lounge. The Illiria's passengers, sipping cocktails and munching on hors d'oeuvres, range in age from their late fifties to their seventies. More than a few are veterans of World War II campaigns in these islands. One woman is a former nurse at Milne Bay, in what is now Papua New Guinea. Another passenger flew patrol bombers out of the Santa Cruz Islands. Another was navigator of a destroyer in the bloody night battles in the Slot, the narrow body of water that leads through the center of the Solomons from Rabaul to Guadalcanal. Still others served in the grim struggle for Bougainville around Empress Augusta Bay.

If battles on land leave many scars and landmarks, battles at sea usually leave no trace -- except perhaps on the sea bottom -- to indicate that once thousands of men traded death and devastation here. The waters between Rabaul and Guadalcanal witnessed more sea battles in the space of about 15 months than occurred in all of World War I. Some of these engagements, such as the Battle of Cape St. George -- a brilliant destroyer action won by future chief of naval operations Arleigh Burke -- are still studied by naval tacticians. It's surprising and enlightening to see just how narrow and restrictive these waters are -- and how dark the nights (when almost all the battles were fought) can be.

Today, the waters of New Guinea and the Solomons are just as narrow and as poorly charted, the weather just as changeable, as when the great captains of World War II fought their famous sea battles there. Except at Rabaul and Vanuatu, the Illiria is unable to dock at a pier or wharf. We use the ship's tenders (auxiliary ships) and, more frequently, her small rubber boats, called Zodiacs, for shore excursions. At low tide even the Zodiacs are sometimes unable to make the beach, and we have to wade ashore carrying cameras and suntan lotion at high port.

Three days after we leave Port Moresby -- and after stops in Samarai and the Trobriands -- we arrive in Rabaul, its spacious harbor surrounded by the majestic peaks of still-active volcanoes. In Rabaul, probably the most heavily bombed town in the South Pacific, we tour the former command bunker of Adm. Kusaka Ryunosuke (chief of staff on the Pearl Harbor raid). This is the same bunker from which Adm. Isoroku Yamamoto departed on his last fatal flight to Bougainville.A short ride from "the admiral's bunker" by mini-bus is a large cave at the foot of a steep, jungle-covered mountain. Inside the cave, rusting away in stately dignity, are three Japanese landing barges. Still on their metal tracks, ready to be rolled out of the cave to a nearby beach or river, they survived all the Allied bombing of the war. Hundreds of barges like these were used by the Japanese to carry supplies and reinforcements to their island bases in the Solomons. Large and slow, called "ant freight" by the troops, they were favorite targets for American PT boats and aircraft.

As we stand in the cave, it is easy to imagine what it must have been like to ride down the Slot on a hot, moonless night in one of these unwieldy hulks, packed with troops or ammunition, as it crept toward its destination, hugging the shoreline and hoping to complete the journey before dawn brought the ever-present Allied aircraft.

Next stop: Bougainville. Several members of our tour had paid an earlier visit -- in March 1944, when, as soldiers in the Americal and 37th Divisions, they had helped to repulse the largest Japanese counterattack in the South Pacific. The attack was aimed at the American airfields at Empress Augusta Bay, which played a big role in the air assault in Rabaul.

The Illiria's itinerary does not include Empress Augusta Bay, but takes the ship to the town of Kieta on the opposite side of the island. One passenger, the former rifle platoon leader, is bitterly disappointed. We briefly consider chartering a plane to fly over the area, but nothing can be arranged in the short time available.

Still, even from Kieta, it is not difficult to visualize what the fighting on Bougainville must have been like. The island still has the smells, sounds and heat of the jungle, with clouds and drizzle alternating with brilliant sunlight several times a day. Despite its vigorous postwar economic development (it has the largest copper mine in Papua New Guinea), many parts of Bougainville still look much the way they do in the somber, brooding charcoal drawings by war artist Kerr Eby.

If Bougainville seems much the same as it did in World War II, Guadalcanal, by contrast, looks somewhat tame and civilized nowadays. This island in the Solomons -- the high point of the tour, from the viewpoint of the World War II aficionado -- was the scene of a bloody air, land and sea struggle that marked the turning point of the war.

Originally thought of as a stepping stone toward Rabaul, the Guadalcanal campaign soon took on a life of its own, a six-month slugging match between the Japanese and Americans in which American control of the small airfield on Guadalcanal, Henderson Field, proved decisive. Both sides suffered heavy losses in ships and planes, but the Americans could replace theirs with new and better ones. The Japanese could not, and for them the war of attrition in the South Pacific was to prove fatal.

Because much of the heaviest fighting on Guadalcanal took place within a few miles of Henderson Field, and the site of the present town of Honiara, capital of the Solomons, we are able to visit most of the sights in a day, by mini-van.

Much of the dense vegetation on Guadalcanal was cleared away later in the war as the island was developed into an important Allied base. Today the jungle has receded and some of the steep slopes and ravines are now gently rolling hills dotted with houses. Yet Red Beach, where units of the 1st, 5th and 11th Marines of the First Marine Division first came ashore in a deceptively easy landing on Aug. 7, 1942, looks much the same as in old photos, and the jungle-covered banks of the Ilu River, which served as the east flank of the Marines' perimeter and the scene of an early battle, seem unchanged after 45 years.

On Mount Austin, we look out from the top of the stark white Japanese war memorial toward Henderson Field. Japanese troops, hungry and racked by tropical diseases, gazed out at this same sight -- the small, primitive airfield that was at once an unattainable prize and a symbol of their unavoidable defeat.

But battlefields and war relics are not the only attractions of the South Pacific. Many of the inhabitants of the Trobriands and Santa Cruz Islands look as if they have just stepped from the pages of an anthropology textbook. In fact, some of them have, since this area was also the site of many classic anthropological studies.

On Tikopia in the Santa Cruz Islands, on one of the rare sunny afternoons, we take a break from battles and go exploring. We go in by rubber boat, stroll along the beach, wander through villages of leaf and bark houses, and bargain for handicrafts with Tikopians who still sport the traditional tattoos and "tapa" clothing.

These seemingly casual excursions take a good bit of arranging. The Illiria's three-hour call at Tikopia was made possible by a $500 donation to the local hospital by the tour company, as well as an additional $500 for the local school -- plus landing fees and gifts of sugar, rice, cigarettes and beer to Tikopia's four principal chiefs. (On this particular trip, the chiefs also received Smithsonian T-shirts.)

Despite the inconveniences and less than idyllic weather, morale on our trip remains high. Toward the end of the tour, we gather in the ship's lounge and talk about our impressions.

Vivian, the former nurse at Milne Bay, had finally discovered the fate of the hospital where 40 years ago she had helped care for the Marines returning from Tarawa. At the Illiria's first stop, tiny Samarai Island, just off the southeast coast of Papua New Guinea, she had learned that the jungle has pretty much taken over the site now -- but that some of the metal from the hospital was used to build the school on the island. "I feel good about that," she says. "I completed my mission and will tell the eight other remaining nurses what I learned."

"I feel as if I offered my youth on that island," says the former rifle platoon leader of his time on Bougainville. "I'm glad I did that, but I feel as if I lost something, and I guess I was looking to get something back ... Seeing the people out here, coming into independence and freedom without bloodshed, makes it seem as if what we did was worthwhile." Ronald Spector, author of "Eagle Against the Sun: The American War With Japan," is at work on a book about the latter years of the Vietnam war.