On a cruise to Copenhagen through the Baltic Sea, the author witnesses an ever-transforming northern Europe during two weeks of white nights.

When I think of cruises, I hear Fred Astaire doing the opening number from the movie Follow the Fleet. You know: "We joined the Navy to see the world/And what did we see?/We saw the sea." Now, I like cruises, but some itineraries have the land-to-water ratio all wrong, and I do feel that Fred and the Navy chorus are justified in not finding the Pacific terrific if the ocean is the main event. So Celebrity's new Baltic route, with stops in seven cities, appealed to me greatly. Oslo, Stockholm, Helsinki, St. Petersburg, Gdansk, Berlin and Copenhagen, it went. Quite a lineup. Many of those places have changed so much in the past decade that the trip looked like an exercise in contrast, a downright discovery tour, a précis of Northern Europe: The Future.

The ship, too, represented the end of a tiny era. We'd be sailing on Galaxy, which had been the star of the Celebrity fleet. Only five years old, she already had three younger--and bigger and sleeker--sisters. But Galaxy was perfectly charming, as it turned out, and the large veranda in my cabin (or stateroom, in cruise vernacular) was great for watching the sun not set during the white nights. What you lose in nightlife you gain in culture. I liked the idea of having several microvacations--without having to pack for each one. In fact, by the end of the 14-day trip, I felt as if I'd been on some kind of sophisticated theme cruise: not one of the old standbys, like gourmet, or golf, but one based on a more ethereal notion--change, perhaps, since both the cruise line and several ports of call were embroiled in furious reconfiguring and expansion.

Another reason for joining Galaxy was that for part of this trip she would be hosting Celebrity's culinary and wine consultant, Michel Roux, chef and owner of England's three-Michelin-star Waterside Inn and himself a bit of a celebrity. He was making one of his quality-control voyages, and I would get to tour the galleys with him and perhaps gain some insight into an aspect of cruise ships I find almost miraculous: catering on a banquet scale three times a day. Galaxy has three restaurants, starring Orion, the main dining room, a glamorous bi-level stadium with a grand staircase and a window the size of an Imax screen, through which we continuously saw the sea. Here, according to ancient cruise-ship tradition, we were offered five courses nightly by our table's own waiters and sommelier (complete with silver tastevin dangling round his neck), who used our first names and always remembered my extra vegetables. Upstairs on the Resort Deck, were Galaxy's casual lunchtime Oasis Grill and Oasis Café, which, since I found them reminiscent of high school cafeterias in both food and ambience, I largely ignored.

I joined the ship in Stockholm, a scenic departure port with views of several of the Swedish capital's islands, including the medieval Gamla Stan and the island where the Nobel Prizes are awarded. (For time reasons, I'd opted to ignore Oslo.) My first port of call was therefore to be Helsinki. Cruise itineraries are timed to maximize sensory impact, so docking and breakfast tend to coincide. (On a short hop, a ship may chug round in circles all night just to give passengers the motion and the morning arrival.) There is something thrilling about docking, even at the not scenic, but very Nordic, Hernesaari cruise pier, a half-hour bus ride from downtown Helsinki. Here I decided to go it alone. I eavesdropped on choir practice in Uspenski cathedral, lunched at a Finnish/Italian family's pizzeria and hit Marimekko, source of those forever-hip, Crayola-colored, stylized flower prints, scoring fabulous clothes and linens not available back home. But it was the breathtaking 1969 Temppeliaukio church, a magical circular structure carved into a hill of granite, that really made the stop worthwhile.

I was anticipating no port more hotly than St. Petersburg, but docking was disappointing since the harbor, quite some distance from the city, is far more Solzhenitsyn than it is Tolstoy. Disembarkation too, though accompanied by an enthusiastic Russian brass band playing "The Colonel Bogie March" and "God Bless America," was more breadline than theme-park line, but things looked up the moment our guide started her commentary. (Having failed to apply for a tourist visa, I was tied to the bus.) Marina was the finest guide I've ever encountered: erudite, witty, and better informed than your average professor about the jaw-dropping Hermitage and its piles of sublime art; Tsarskoye Selo, Catherine the Great's incredible palace; and their restorations and histories and just about everything else having to do with them. Best of all, she was honest, advising us which of the thronging matryoshka nesting-doll and lacquer-box sellers to avoid and telling us that the jars of osetra caviar the Typical Russian Lunch waiters were selling for $10 under the table were the same as the $78 official ones. Neither did she shrink from discussing the decay obvious on every beautiful street and the maddening economy, in which gangsters have fancy apartments and highly educated, skilled people sell matryoshka dolls.

After two days in St. Petersburg, life on Galaxy was quite the contrast, especially when everyone trotted out their rhinestones and tuxedos for formal night. But Michel Roux had arrived, and so before dinner we found time to visit the galleys. By now a veteran of a dozen Galaxy meals, I had decided that treading the line between populist and elitist, between comforting and impressive, was a difficult trick that Roux and his team pulled off consistently well at Orion, where lunch might be watermelon gazpacho and quesadillas; dinner appetizers ranged from Parma ham with melon and figs to sweetbreads with crisp potato pancakes, entrées from prime rib au jus with baked potato to seared cod on spinach with fennel-and-lychee chutney. Most of the dishes I tried were fine to excellent, with only the pastas a dead loss.

Alongside the director of food operations, Alfred Goldinger, Roux has been in charge of the cuisine at Celebrity for all of its 12 years, overseeing 140-odd food preparers per ship, even taking the top chefs to his own restaurant to train. Each ship serves the same dishes. "When I have one of my fantasy ideas, I try it out on one ship, then spread it to all of them," he says. "I play. I get good ideas from traveling, from markets in Hanoi, Bangkok, Chiang Mai ..." And yes, he happily admits that cruise catering is banquet cooking--though on the newest ships, in line with the general cruise trend, the banquet is refracted into more and smaller restaurants, including a formal, reservations-only one starring (Celebrity claims) the first seagoing tableside flambéing.

Another day, another former Communist country. This was Tuesday and therefore Poland, and although Gdynia was another ugly port, it didn't matter because our destination was inland, in Gdansk. How I'd looked forward to Gdansk. Its recent history alone, I thought, would sing from the stones in this thousand-year-old metropolis that became the free city of Danzig after WWI, kicked off WWII with Hitler's invasion, was razed by Allied bombs then completely reconstructed during the Soviet era, and which, as home to Lech Walesa, became the birthplace of Solidarnosc in the early 1980s. But, unfortunately, the meticulously replicated classical, baroque and rococo houses along Droga Krolewska (the Royal Way) and Gothic and Renaissance Ratusz (town hall) seemed curiously soulless as our guide (who was no Marina) walked us to the amber sellers who took American Express on the banks of Motlawa River. On the bright side, these jewelers were well up on the latest settings, so I added Polish amber to my stash of Finnish tablecloths and Russian caviar; then, though I craved a regular grocery store in which to spend my zlotys, Galaxy's thalassotherapy pool and martini bar won out. Ah, well. Tomorrow was the port of Warnemünde, and thence Berlin.

Since the German capital is three hours south of Warnemünde, I took another of Celebrity's optional tours, but abandoned the bus at the Brandenburg Gate and walked east, destination, Prenzlauer Berg. The elegant houses and leafy squares of Prenzl'berg, as it is known, are still cheap enough for young artists and café and bar proprietors to play with. It's one of the hot neighborhoods of former East Berlin, a vibrant quarter with change on every corner, not to mention beer gardens and restaurants Thai, Italian, Sri Lankan, Ghanaian--even German. I explored the shops and galleries of cobbled Knaackstrasse and ate wurst at a sunny sidewalk table at the restaurant Weitzmann in bucolic, bustling Kollwitzplatz surrounded by laid-back locals and their dogs, then drank in the gorgeous garden at the old brewery, Pfefferberg. It hit the spot. I felt like a Berliner, miles away from any cruise ship, and I had to remind myself repeatedly that it would not be fun to miss the boat. That's what I'll do again next time, I thought, pick one neighborhood to explore, rather than try to see the whole city.

But I'd run out of ports to practice on. The next day we glided past Den Lille Havfrue--the Little Mermaid statue--and docked in Copenhagen, where I'd opted to disembark. It seemed an appropriate finish, since Galaxy was about to exit the Baltic for the North Sea. In September 2001, she left Europe altogether, ceding both the North Sea and the Baltic to her brand new sister Constellation. Obviously Fred and the boys were following the wrong fleet.

(Celebrity Cruises' next Northern Europe trip will be from June 8 to 22; 800-722-5941 or www.celebritycruises.com.)