NEW YORK – Elizabeth Hardwick, a Kentucky-born author and critic with Maine ties whose incisive prose helped her fulfill her dream of becoming a “New York intellectual,” has died. She was 91.

Hardwick, who maintained a summer residence for many years in Castine, died Sunday in her sleep at Roosevelt Hospital, according to Catherine Tice, associate publisher of The New York Review of Books, which Hardwick helped found in 1963. She had been hospitalized with a minor infection.

Hardwick was among the last survivors of a promiscuous, hard-drinking circle of intellectuals that included Lionel Trilling and celebrated poet Robert Lowell, with whom she had a famously difficult marriage.

She married Lowell in 1949 and suffered through his infidelities and manic-depression, endlessly leaving her and then changing his mind. They divorced in 1972.

The couple were part of what Time Magazine once labeled “Castine’s Literary Colony” – an unprecedented period during the 1960s and 1970s when poet Philip Booth and novelist-critic Mary McCarthy summered near Hardwick and Lowell.

Hardwick was a loyal friend and had a great fondness for Castine, according to local writer Deborah Joy Corey whose friendship with the author spanned the past 15 years and who considered Hardwick her mentor. Even though there was a big difference in their ages, Corey said, Hardwick took her under her wing professionally and became an “instant girlfriend.”

“Lizzie had the ability to cross generations like that; there were always people of different ages, different personalities around her,” Corey said. “She was as interested in an architect as in a fishermen. She had such a natural curiosity. Everyone interested her. I think that was what made her such an excellent writer.”

Hardwick continued to visit Castine well into her 80s but her visits ended several years ago when she was no longer able to travel. She remained interested in the town and kept up on everyone there, Corey said.

“She had a love affair with Castine,” Corey said. “This was a place she related to most, even beyond her original home. She spent some of her best years here.”

Although she started out as a fiction writer, Hardwick received her greatest acclaim as a critic. “Seduction and Betrayal,” an analysis of such literary heroines as Hester Prynne of “The Scarlet Letter,” became required reading for studies of women in fiction.

Hardwick also helped found an essential highbrow publication: The New York Review of Books. It was conceived during a newspaper strike in New York City, when she and Lowell were lamenting with friends Jason and Barbara Epstein over the poor state of literary criticism.

Her first novel, “The Ghostly Lover,” came out in 1945 and related the conflicts of a middle-class Kentucky family. Diana Trilling, reviewing the book, compared her to Eudora Welty and D.H. Lawrence.