Ellen Hovde, a documentarian who was one of the directors of “Grey Gardens,” the groundbreaking 1975 movie that examined the lives of two reclusive women living in a deteriorating mansion on Long Island and inspired both a Broadway musical and an HBO film, died on Feb. 16 at her home in Brooklyn. She was 97.

Her death, which had not been widely reported, was confirmed last week by her children, Tessa Huxley and Mark Trevenen Huxley, who said the cause was Alzheimer’s disease.

Ms. Hovde (pronounced HUV-dee) worked on several films with the Maysles brothers, Albert and David, in the late 1960s and ’70s, when they were expanding the documentary form with cinéma vérité techniques, eschewing sit-in-a-chair interviews in favor of recording life and events as they happened.

In 1969 she was a contributing editor on “Salesman,” a documentary by the Maysleses and Charlotte Zwerin that followed four salesmen as they peddled $49.95 Bibles door to door in New England and Florida. The next year she was an editor on “Gimme Shelter,” the documentary by the Maysleses and Ms. Zwerin that captured a Rolling Stones tour, including the concert at Altamont Speedway in Northern California in late 1969 at which a concertgoer was killed by a Hells Angel.

In 1974 she was credited as a director, along with the Maysleses, on “Christo’s Valley Curtain,” which was about an environmental art project the artists Christo and Jeanne-Claude erected in Colorado in 1972. That film was nominated for an Academy Award for best documentary short.

The next year came “Grey Gardens.” That film, which garnered considerable attention at the time and in 2010 was named to the National Film Registry of culturally significant movies, took a close-up, often uncomfortable look at the lives of Edie Beale and her mother, Edith Beale, relatives of Jacqueline Kennedy Onassis who had dropped out of high society and were living in East Hampton, N.Y., in a crumbling mansion along with assorted cats and raccoons.

The film came about somewhat by accident when Lee Radziwill, Ms. Onassis’ sister, suggested that the Maysleses and Ms. Hovde make a documentary about her childhood. Among the people she suggested they talk to were the Beales — Little Edie and Big Edie, as they were known. The documentary Ms. Radziwill had suggested fell through, but the Maysleses and Ms. Hovde were intrigued by the Beales and proposed a film to them.

“Big Edie didn’t really want to do it at first,” Ms. Hovde said in a 1978 interview with Film Quarterly. “Little Edie did.”

Soon Muffie Meyer, who would partner with Ms. Hovde on numerous films in the ensuing years, joined the project. Ms. Hovde and Ms. Meyer received directing credits on the film along with the Maysles brothers, but they, in addition to Susan Froemke, were also its editors, which to Ms. Hovde was the pivotal role.

“The person who is doing the editing is doing something very like a mix of writing and stage directing,” she told Film Quarterly. “That person is shaping, forming and structuring the material, and making the decisions about what is really going to be there on the screen — what the ideas are, what the order of events will be, where the emphasis will be.”

For “Grey Gardens,” that involved going through dozens of hours of film and shaping a portrait that revealed the codependent relationship between the two eccentric women. Ms. Meyer said that, if portable cameras and tape recorders made the type of filmmaking used in “Grey Gardens” possible, the other crucial element was the editing.

“Essentially, massive amounts of footage (usually upwards of 60 hours), unscripted and with little or no direction, was dumped in the editing room,” she said by email. “The editor’s job was to screen it, organize it, take careful notes, and then find the story and the structure. Ellen was a master at all of this, and there are not many masters (Charlotte Zwerin was another).”

“Grey Gardens” drew both acclaim and disapproval from critics. The film critic Roger Ebert called it “one of the most haunting documentaries in a long time.” But in The New York Times, Richard Eder, while acknowledging that there was “no doubt about the artistry and devotion” involved in making the film, said that “the moviegoer will still feel like an exploiter.”

The debate over whether “Grey Gardens” and other films in the same style exploit their subjects or invade their privacy has been an ongoing one, and there was a chorus of such complaints when the movie was released. But Ms. Hovde, in the Film Quarterly interview, said the Beales themselves disputed that interpretation.

“In the months when there was a lot of controversy about it,” she said, “it was Mrs. Beale and Edie who called us and said: ‘You know there has been this criticism — don’t worry. It’s all right. We know that it is an honest picture. We believe in it. We don’t want you to feel upset.’ That was their attitude, and they never wavered from that.”

A musical based on the documentary opened on Broadway in 2006 and won three Tony Awards, and in 2009 HBO’s “Grey Gardens” movie, with Jessica Lange and Drew Barrymore as the Beales, won six Emmy Awards.

In 1978 Ms. Hovde and Ms. Meyer formed Middlemarch Films, which went on to make scores of documentary features and videos in various styles and on a wide range of subjects. Some explored subjects from the age before film and photography and used actors to re-create scenes. One of those, a television mini-series about Benjamin Franklin directed jointly by Ms. Meyer and Ms. Hovde in 2002, won an Emmy for outstanding nonfiction special.

Ms. Meyer said that in those types of projects, Ms. Hovde was a stickler for accuracy.

“One example was her insistence on the accuracy of the bird tweets and frog sounds in our colonial-period films,” she said. “She drove the sound editors to distraction (and in one late-night session, to tears): ‘Was this frog endemic to the Northeast and did it croak in late fall?’ ‘Was this bird tweet that was added to the soundtrack really a bird that could be found in Virginia in the 18th century?’”

Ellen Margerethe Hovde was born on March 9, 1925, in Meadville, Pa. Her father, Brynjolf (known as Bryn), was president of the New School for Social Research from 1945 to 1950, and her mother, Theresse (Arneson) Hovde, was a nurse.

Ms. Hovde grew up in Pittsburgh and earned a degree in theater in 1947 at the Carnegie Institute of Technology, after which she studied for a time at the University of Oslo. In 1950 she married Matthew Huxley, son of the author Aldous L. Huxley. The marriage ended in divorce, but Ms. Hovde’s son said that she and Aldous Huxley remained close until his death in 1963, and that as his eyesight began to fail, she would sometimes read books into a tape recorder for him.

Ms. Hovde had hoped for a career as a stage director, but, after not finding work, she took a job as an administrative assistant at a film school. By the early 1950s she was learning editing. Her credits before she began working with the Maysles brothers included editing “Margaret Mead’s New Guinea Journal” (1968) for the New York public television station WNET and a Simon and Garfunkel television special broadcast on CBS in 1969.

Ms. Hovde’s second marriage, to Adam Edward Giffard in 1963, also ended in divorce. In addition to her children, she is survived by two grandchildren.

Ms. Meyer said Ms. Hovde’s homes were gathering places for documentarians in the 1970s, and she once helped organize a filmmakers’ cookbook, a photocopied collection of everyone’s favorite recipes.

“Most of us still use it,” she said.