I learned a lot about these fishermen, and developed lasting friendships with them. Lucien Vitiello, the weathered leader of the group, spent the most time with me, and taught me about the passion that drives these men to devotedly pursue such a harsh existence. On many occasions, I would join him on the Irene, his loud, slow boat, and listen as he spun tales of the Mediterranean and its fish, and little by little revealed the unwritten rules by which he and his fellow fishermen live. We passed some unsuccessful days together on the boat, and some good days, and even a few great days—days when we'd pull into port, our spirits high, with copious hauls of grondin, congre, baudroie, loup, chapon, saint-pierre, and the esteemed dorade. Fruitful times such as these inspired stories about bouillabaisse, the local fisherman's dish that's best when made with as wide a variety of fish as possible. I'd heard the fishermen boast about their "bouilla" and argue about what should go into the dish—and what never should. I'd heard about the world's largest version, "La Geante", prepared in Sanary under Vitiello's guidance every June—and about how the tradition had grown out of a dinner conversation that Vitiello had eight years ago with the town's mayor. Over time, I came to understand that Vitiello was a master of bouillabaisse.

I'd eaten delicious bouillabaisse in restaurants before, enjoying the soup and then the whole fish in the classic two-part service, but I'd never developed a real affinity for the dish. After spending months at sea with the fishermen, though, and hearing the reverence and emotion that seasoned their talk, I knew I had missed something. I was intrigued and wanted to know why the dish held such a special place in their hearts. So, when Vitiello at last invited me to his home to partake of a Sunday bouillabaisse, I was honored and delighted. I asked to come early to watch him cook. He accepted.

Provençal bouillabaisse starts with good olive oil, onions, garlic, fennel, tomatoes, saffron, and a bouquet garni. The other potential ingredients—leeks, potatoes, orange peel, pastis (the anise-flavored Provençal aperitif), even shellfish—are the subject of heated debate. Even the choice of fish is disputed. Most local cooks insist on rascasse, but after that, everyone seems to have his own strong opinion. About the only thing commonly agreed upon is that the seafood used must be Mediterranean.

While some fishermen along the 40-mile stretch of jagged coastline between Marseille and Toulon claim bouillabaisse as the centuries-old creation of their Provençal predecessors, there are other more fanciful theories concerning its origins. Curnonsky, acclaimed as the Prince des Gastronomes, once proposed that angels carried the first bouillabaisse from heaven to nourish shipwrecked saints. Another myth has Venus, the goddess of love, preparing the soup for her husband, Vulcan, to lull him to sleep so that she could dally with Mars. The French author and poet Joseph Mery, on the other hand, assigned credit for the dish to the abbess of a convent in Marseille. And one G. A. Ortolan, in a book called La Legende & l'histoire de la bouillabaisse, published in 1891, says that it was invented by a Provençal widow who made a stew of everything she had in the kitchen, to welcome home her long-lost son.

It's fairly certain that whoever cooked the first bouillabaisse did so in a big pot over a hot fire—hence its name, which derives from the words bouillir, to boil, and abaisser, to lower. All authentic bouillabaisse recipes call for the ingredients to be brought to a quick and rapid boil (a "true tempest of fire", as one recipe puts it). This causes the oil, stock, and fish gelatin in the pot to emulsify into a rich, satisfying broth. The quality of the broth is essential to the dish if it is to be presented in the time-honored manner, in two courses—first the soup, poured over croutons topped with rouille, then the fish and, if they're included in the recipe, potatoes. (Elegant restaurants may present a third course of langouste, or spiny lobster, if they're part of the recipe.)

On a beautiful spring afternoon, I arrived at Lucien Vitiello's home in the hills above Sanary. My host immediately put me to work slicing onions and potatoes while he cleaned a large accumulation of fish, most of which he had netted the day before. He pointed out the soft-fleshed varieties—rouquier (wrasse) and mostelle (forkbeard), which would disintegrate during cooking and enrich the soup—and then the firmer ones: saint-pierre (john dory), congre (conger eel), vive (weever), and, of course, rascasse (scorpion fish), all of which would be served whole. Some say that using both soft and firm fish makes a better bouillabaisse—but Vitiello says it's not essential. As he put it, "You use what you are lucky enough to catch."

After cleaning the fish, Vitiello poured some fruity olive oil into an enormous pot, scattered the onions and garlic into it, then added some fennel tops and herbs. Tomatoes and sliced potatoes went in next, then the fish, which were topped with a few more tomatoes. He doused everything with richly scented fish stock, tossed in a handful of favouilles (small Mediterranean crabs) and another of mussels, then gave the entire dish a spritz of pastis and a big pinch of saffron. His bouillabaisse was now ready for the fire.

We left the pot and walked outside to join Vitiello's friends, a cross-section of Sanary—politicians, teachers, shopkeepers, fishermen, and their kids—who had gathered in the yard. Children scurried around, darting behind fragrant mimosa trees. I sipped cold pastis and enjoyed the company of Lucien's wife, Loulou. As she and I chatted, Vitiello and a fisherman friend of his retrieved the bouillabaisse pot and carried it to a propane stove outside the kitchen door, where they set it over a high flame. A lovely aroma began wafting our way. Less than an hour later, Loulou called out: "À table!"

We took our places on the terrace, at two long tables set with colorful Provençal pottery. We drank chilled rose wine from nearby Bandol and nibbled plump anchovies that Vitiello had cured himself. Plates of toasted baguette rounds and bowls of deep orange rouille were set before us. We daubed the slices of bread with rouille and put them in our empty bowls. Vitiello appeared with a tureen of steaming fish soup and generously ladled this heady distillation of sea and sun over our croutons. It was thin but intense, a quintessence of fish with a delicate veil of olive oil and anise. The pungent rouille contrasted nicely. When we had finished the soup, Vitiello brought us a carved cork platter heaped with saffron-tinted fish, shellfish, and potatoes. He skillfully portioned the larger fish, left the smaller ones whole, and lifted a few pieces onto each plate. I tasted the intense rascasse and firm-fleshed saint-pierre, both distinctive in flavor, and the sublimely subtle congre.

As we ate, I looked around at my companions and saw a dozen good souls sharing a love of food and drink and an honest affection for our host and his wife. I sipped some cool wine, drank in the sweep of the Mediterranean in the distance, and knew that I understood—that I felt—what bouillabaisse means to the fishermen of Sanary. And I knew that I'd hold on to that feeling for years to come.