On a moonless January night in 2003, Olivier de Kersauson, the French yachtsman, was racing across the Atlantic Ocean, trying to break the record for the fastest sailing voyage around the world, when his boat mysteriously came to a halt. There was no land for hundreds of miles, yet the mast rattled and the hull shuddered, as if the vessel had run aground. Kersauson turned the wheel one way, then the other; still, the gunwales shook inexplicably in the darkness. Kersauson ordered his crew, all of whom were now running up and down the deck, to investigate. Some of the crew took out spotlights and shone them on the water, as the massive trimaran—a three-hulled, hundred-and-ten-foot boat that was the largest racing machine of its kind, and was named Geronimo, for the Apache warrior—pitched in the waves.

Meanwhile, the first mate, Didier Ragot, descended from the deck into the cabin, opened a trapdoor in the floor, and peered through a porthole into the ocean, using a flashlight. He glimpsed something by the rudder. “It was bigger than a human leg,” Ragot recently told me. “It was a tentacle.” He looked again. “It was starting to move,” he recalled.

He beckoned Kersauson, who came down and crouched over the opening. “I think it’s some sort of animal,” Ragot said.

Kersauson took the flashlight, and inspected for himself. “I had never seen anything like it,” he told me. “There were two giant tentacles right beneath us, lashing at the rudder.”

The creature seemed to be wrapping itself around the boat, which rocked violently. The floorboards creaked, and the rudder started to bend. Then, just as the stern seemed ready to snap, everything went still. “As it unhooked itself from the boat, I could see its tentacles,” Ragot recalled. “The whole animal must have been nearly thirty feet long.”

The creature had glistening skin and long arms with suckers, which left impressions on the hull. “It was enormous,” Kersauson recalled. “I’ve been sailing for forty years and I’ve always had an answer for everything—for hurricanes and icebergs. But I didn’t have an answer for this. It was terrifying.”

What they claimed they saw—a claim that many regarded as a tall tale—was a giant squid, an animal that has long occupied a central place in sea lore; it has been said to be larger than a whale and stronger than an elephant, with a beak that can sever steel cables. In a famous scene in “20,000 Leagues Under the Sea,” Jules Verne depicts a battle between a submarine and a giant squid that is twenty-five feet long, with eight arms and blue-green eyes—“a terrible monster worthy of all the legends about such creatures.” More recently, Peter Benchley, in his thriller “Beast,” describes a giant squid that “killed without need, as if Nature, in a fit of perverse malevolence, had programmed it to that end.”

Such fictional accounts, coupled with scores of unconfirmed sightings by sailors over the years, have elevated the giant squid into the fabled realm of the fire-breathing dragon and the Loch Ness monster. Though the giant squid is no myth, the species, designated in scientific literature as Architeuthis, is so little understood that it sometimes seems like one. A fully grown giant squid is classified as the largest invertebrate on Earth, with tentacles sometimes as long as a city bus and eyes about the size of human heads. Yet no scientist has ever examined a live specimen—or seen one swimming in the sea. Researchers have studied only carcasses, which have occasionally washed ashore or floated to the surface. (One corpse, found in 1887 in the South Pacific, was said to be nearly sixty feet long.) Other evidence of the giant squid is even more indirect: sucker marks have been spotted on the bodies of sperm whales, as if burned into them; presumably, the two creatures battle each other hundreds of feet beneath the ocean’s surface.

The giant squid has consumed the imaginations of many oceanographers. How could something so big and powerful remain unseen for so long—or be less understood than dinosaurs, which died out millions of years ago? The search for a living specimen has inspired a fevered competition. For decades, teams of scientists have prowled the high seas in the hope of glimpsing one. These “squid squads” have in recent years invested millions of dollars and deployed scores of submarines and underwater cameras, in a struggle to be first.

Steve O’Shea, a marine biologist from New Zealand, is one of the hunters—but his approach is radically different. He is not trying to find a mature giant squid; rather, he is scouring the ocean for a baby, called a paralarva, which he can grow in captivity. A paralarva is often the size of a cricket.

“Squid, you see, hatch thousands of babies,” O’Shea told me recently, when I called him at his office at the Earth and Oceanic Sciences Research Institute, at the Auckland University of Technology. “Most of these will get eaten up by larger predators, but during periods of spawning the sea should be filled with an absolutely fantastic amount of these miniature organisms. And, unlike the adults, they shouldn’t be able to dart away as easily.”

Rival hunters once viewed his plan skeptically: if no one could find the animal when it was sixty feet long, how could anyone discover it when it was barely an eighth of an inch? Lately, though, many have come to see O’Shea’s strategy as a potential breakthrough. “It offers several advantages,” Clyde Roper, an American who is perhaps the world’s foremost expert on squid, told me. Roper is a giant-squid hunter himself, who once descended underwater in a steel cage, in search of his quarry. “First, you could find the juvenile at shallower depths. That makes it a lot easier to catch. Furthermore, there are more of them around, because at that stage, even though mortality is high, the adult female will release up to four million eggs. That’s a hell of a lot of baby giant squid running around.” He added, “It’s a matter of a numbers game, pure and simple.”

In 1999, O’Shea studied what few had ever seen—the corpse of a baby Architeuthis, which was discovered off New Zealand. He described its curious morphology: two eyes spread disconcertingly far apart; a parrot-like mouth concealing a raspy, serrated tongue; eight arms extending outward from a torpedo-shaped head. Each elastic limb was lined with hundreds of suckers, ringed with sharp teeth. The skin was iridescent, and filled with chromatophores—groups of pigment cells—that allowed it to change colors. A funnel near its head could shoot out clouds of black ink. The specimen also had two extraordinary-looking clubbed tentacles. (When a giant squid is mature, they can stretch up to thirty feet.)

Armed with this rare expertise, O’Shea has spent the last five years mapping out where to find a baby giant squid and puzzling over how to catch one and grow it in a tank. This year, he told me, he would venture out during the summer nights of the Southern Hemisphere, when giant squid released their babies. “Come on down, mate,” he said. “We’ll see if we can’t find the bloody thing and make history.”

The bodies of dead giant squid have been found in nearly every ocean: in the Pacific, near California; in the Atlantic, off the coasts of Newfoundland and Norway; and in the Indian, south of South Africa. But no place is considered better for hunting giant squid than the waters around New Zealand. It is here that currents from the tropics and Antarctica converge, and the resulting diversity of marine life creates an abundance of plankton for squid to feed on. And it is here that, in recent years, more dead giant squid have been recovered than anywhere else.

I arrived in Auckland on a morning in late February, and O’Shea greeted me at the airport. He looked much younger than his age, thirty-eight. He wore khaki pants and a khaki-colored shirt, a uniform that evoked a safari ranger. He is small and trim, and has brown hair, which was sticking up as if he had just run his fingers through it. Peering through spectacles that made his eyes seem abnormally large, he confessed with some embarrassment that he had come for me the previous day. “I’ve been preoccupied with everything that’s happening,” he said.

He spoke in a soft yet intense murmur, and whenever I addressed him he would turn his head sideways, so that I was talking directly into his right ear. (Later, he told me that he had damaged his left ear in a diving accident.) He reached into his wallet and pulled out his business card; beside his name was a picture of an iridescent squid. While I was looking at it, he grabbed one of my bags and hurried to his truck, which, as soon as he opened the driver’s door, exhaled a strange, pungent odor. “I do apologize,” he said, as he rolled down the windows. “You’ll find that everything around me smells of dead squid and ciggies.” In the back seat was a metal pole that was three feet long, with a net on the end. I soon discovered that he carried it with him wherever he went, often slung over his shoulder, as if he were a butterfly hunter.

Over the next few days, we began making preparations for our maiden voyage. At one point, we were speeding down the highway, heading to the store for supplies, when he slammed on the brakes and reversed, in the middle of traffic. “I almost forgot,” he said, parking in a lot that overlooked a harbor. He leaped out with the net and darted down a wharf, a lit cigarette dangling from his mouth. He leaned over the edge, the winds buffeting his face, and held the net high over his head. For a moment, he didn’t move or breathe. “There,” he said, and lunged with the net, slashing at the water. As he pulled the net in, his pant legs wet with spray, I glimpsed a dozen silvery sprat—a minnow-like fish—dancing in the mesh. “I know I look a bit like a bugger,” he said. “But these things are rather important.”

After he flung the net into the water several more times (“Believe it or not, there is a technique to this,” he said), he returned to his truck and tossed the sprat into a white bucket in the back seat. We travelled farther down the road, the sprat jostling behind us, and eventually stopped at an aquarium called Kelly Tarlton’s Antarctic Encounter and Underwater World. (In its brochures, O’Shea was hailed as the “world-renowned squid man.”)

He grabbed the bucket, and we headed inside. “This is where I keep them,” he told me. He led me into a damp room with fluorescent lights, in which there was a round glass tank; inside, darting from side to side, were seventy baby squid, each an inch long. O’Shea explained that these squid, which are found in coastal areas, were a smaller species than Architeuthis. “Look at them,” he said. “They’re bloody marvellous, aren’t they?”

O’Shea is one of the few people in the world who have succeeded in keeping not only coastal but also deep-sea squid alive in captivity. Unlike an octopus, which, as he put it, “you can’t kill, no matter how hard you try,” a squid is highly sensitive to its environment. Accustomed to living in a borderless realm, a squid reacts poorly when placed in a tank, and will often plunge, kamikaze-style, into the walls, or cannibalize other squid.