Martha’s Vineyard has a leading role in Nantucket author Elin Hilderbrand’s 19th novel. The Identicals is The Parent Trap all grown up and sent out to sea. Twin sisters Harper and Tabitha Frost spent most of their adult life apart and estranged; Harper on the Vineyard with their father and Tabitha on Nantucket with their mother. After the death of their father, they switch Islands, stepping into each other’s lives and turning their worlds upside down.

Elin Hilderbrand has been living year-round on Nantucket for 24 years, but she visited the Vineyard first, back in 1989 during a summer break. It was five years later that she settled on Nantucket. She’s always been a writer, even winning the “top author” award in second grade, but Nantucket was the magic that turned her passion into a career. Actually, it started when she left Nantucket to go to Iowa for the graduate fiction writing workshop. She soon discovered that the landlocked, cornfield landscape of Iowa was not to her liking.

“I was so miserable...I am at the best school in America and I am miserable,” she recalled. So she wrote her escape. It became her first novel, The Beach Club, published in 2000.

Over the years, Ms. Hilderbrand has continued to write her best-selling novels long-hand; on the beach, at little league games and everywhere in between while raising three children. On Tuesday, May 2, she will be the featured speaker at the Martha’s Vineyard Chamber of Commerce breakfast, held at the Winnetu Oceanside Resort. She will talk about her latest book as well as how to build a brand.

The Identicals was born out of a few inspirations. Of course there was the Parent Trap, but there was also an interest in the Vineyard from her readers. The author travels the country promoting her books, and inevitably someone in the audience will say, “you know, I’m really a Vineyard person.”

To write the Vineyard half of The Identicals, Ms. Hilderbrand needed to do some research. She usually comes to the Vineyard about twice a year, for book signings and baseball games, but she wanted an off-season experience. The solution: a two-day mid-winter visit. She called upon two Vineyard friends to show her around, spending one evening at Sharky’s and the other at the Ritz. During the day, she explored the towns, ambled around Mytoi and went for runs in Katama.

“I so rarely get to be by myself,” she said, remembering the day in Mytoi. “There was not a soul there, I sat and I thought. Mytoi gardens has a very seminal role in my novel.”

After her two-day reconnaissance mission, Ms. Hilderbrand turned to the internet. She joined Vineyard Facebook group Islanders Talk and asked for help.

“Everybody pitched in when I asked a question,” she said. “Nobody was angry or rude. I had an open, friendly, generous experience.”

Harper and Tabitha are not the first twins to show up in Ms. Hilderbrand’s writing. She has an affinity for twins because she is one. Ms. Hilderbrand is six minutes older than her twin brother Eric, a fact she lists on the back of her novel.

“I can at least see partway into the twin mentality because there was always someone with me,” she said. “Eric and Elin, Eric and Elin, we were a match set.”

Like the Vineyard and Nantucket, Harper and Tabitha share some traits and yet are remarkably different. They are personifications of the two Islands. From Ms. Hilderbrand’s experience, the Vineyard is aggressively low key while Nantucket is wound a bit tighter.

“In regards to Tabitha and Harper, Harper has no pretensions, she’s laid back,” she said. “Tabitha is keyed up, she’s uptight.”

Ms. Hilderbrand admits that her views of the Islands are skewed by her personal relationship to them.

“I love them both, obviously Nantucket is my home, and having it be my home, all the stress is here, all the relationships you built for 24 years, no one is purely good or purely bad,” she said. “On the Vineyard it’s more a love-love relationship.”

The breakfast with Elin Hilderbrand begins at 8:30 a.m. on May 6 at the Dunes Restaurant at the Winnetu, and is sponsored by the Martha’s Vineyard Chamber of Commerce. Tickets are $35 for chamber members and $45 for nonmembers.