PORTLAND – Linda Greenlaw was one of the North Atlantic’s best swordfish boat captains when she quit in 1996, moving to a small Maine island to fish for lobsters.

It was an abrupt lifestyle change for the woman who became famous as the skipper of the Hannah Boden in the high-seas thriller “The Perfect Storm.”

“The biggest difference is that swordfishing is more of an adventure,” she says, then adds diplomatically: “I don’t say there’s a lot more to it, because I think that’s insulting to lobster fisherman. But it’s more exciting.”

If Greenlaw seems wistful for the thrills of swordfishing, she also realizes what she has gained by moving to Maine’s Isle au Haut – a sense of tranquility, closer ties with her family, and a new career as a best-selling author.

In 1999 she wrote “The Hungry Ocean” about a 30-day swordfishing trip to the Grand Banks off Newfoundland.

Her second book, “The Lobster Chronicles,” has risen to No. 2 on the New York Times’ nonfiction best-seller list.

Greenlaw, 41, says the time she spends on her lobster boat, and returning home each night, helps focus her writing.

“The lobstering is so different from the writing – well, it’s almost therapeutic to get out on the boat,” she says.

In “The Lobster Chronicles,” Greenlaw ruminates on lobster fishing and everyday life on an island that depends on the fickle creatures for its economic survival. Both experiences have their joys and frustrations.

Much of the book is based on Greenlaw’s 1997 lobster fishing season, her first on Isle au Haut, a small island with just 40 year-round residents.

For four years from 1997 to 2000, Maine lobster fishermen set records for volume caught. But 1997 turned out to be a bad year on Isle au Haut, causing financial worries for Greenlaw.

At the time, she was not yet a successful author, and her entire savings was invested in fishing gear and her boat, the Mattie Belle.

Greenlaw grew up in Topsham but spent childhood summers on Isle au Haut, and she writes about her sometimes hapless attempts to avoid controversy in a community peopled with eccentric characters.

“There’s something really unique about islanders, and quirky, no doubt,” she says. “I could have written a fairy tale about the island … but it would have been so unrealistic.”

One contentious issue on Isle au Haut is how far lobster fishermen should go in keeping outsiders from invading their turf.

Greenlaw believes island fishermen should protect their lobster stocks and their turf, even if it means illegally cutting lines and destroying valuable gear that belongs to competing fishermen.

At one point in the book, she writes about seeing foreign buoys in waters fished exclusively by Isle au Haut residents.

“The placement of the buoys was the throwing down of a gauntlet, a challenge to go to war. I, for one, was ready.”

Such feuding among lobstermen has led to fistfights, boat rammings and gun brandishing incidents in past years in other parts of Maine. But things remain peaceful on Isle au Haut, despite debate over potential retaliation.

Greenlaw says islanders worry that establishing an exclusive fishing zone would cut off lobstermen from nearby Stonington who have been fishing the waters around Isle au Haut for decades.

“There’s a reason that these people live on this island, and it’s not because they like conflict,” she says. “There’s not an islander that I know who would go out and start cutting hell out of someone’s gear.”

Greenlaw is related to about one-third of Isle au Haut’s year-round residents, and “The Lobster Chronicles” is also a story about family.

When she moved to the island, Greenlaw moved back into her parents’ house after two decades away. Her father, a retired business executive, became her constant companion at sea.

Greenlaw’s writing career grew out of the success of Sebastian Junger’s book “The Perfect Storm,” in which she was described by the author as one of the East Coast’s best fishing captains.

She was wooed to write “The Hungry Ocean,” which became a critical and commercial success, and later was approached about a follow-up.

“I said, ‘Yeah, I’d like to write a novel,”‘ recalls Greenlaw, a former Colby College English major. “And they said, ‘Nooooooo.”‘

Greenlaw negotiated a two-book deal, the first half of which is “The Lobster Chronicles,” so that she eventually could write a novel.

But with her new book’s success, Greenlaw has been questioning whether she should abandon nonfiction, she says. In any case, she plans to start working on her next project when her book tour ends in October.

Greenlaw says she plans to remain on the island, where she now has her own house, but she does seem to miss her more adventurous days as a swordfisherman.

“I have fished from the north coast of Brazil almost up to Labrador – all over the north Atlantic Ocean chasing swordfish,” she says.

Lobstering has its advantages, but the thrill of the chase isn’t one of them. “I’m not really crazy about lobstering,” she admits.