LOS ANGELES — Elaine Dundy, a novelist, biographer, journalist, and memoirist who wrote about her turbulent marriage to legendary critic Kenneth Tynan and their life among the rich and famous, died May 1 at her Los Angeles home. She was 86.

The cause was a heart attack, according to her daughter, Tracy Tynan.

Dundy was the author of several books, the best known of which are “The Dud Avocado” (1958), a novel about a young woman who comes of age in the 1950s through a series of misadventures in decadent Paris; and “Elvis and Gladys” (1985), a biography of Elvis Presley that homes in on his relationship with his mother.

She also wrote “Life Itself!” (2001), a memoir that focuses on her 13-year marriage to Tynan, the theater critic and New Yorker writer who finally drove her away with his demands for sadomasochistic sex. In between the beatings and arguments was a charmed life amid the literati and Hollywood and theatrical elite, including Ernest Hemingway, Tennessee Williams, Laurence Olivier, Gore Vidal, and Orson Welles.

“She was a great wit,” Mr. Vidal, who knew her for 50 years, said Monday. “There was no one else quite like her. She introduced a whole style, the freed American girl landing on old Europe, starting in Paris and moving on to London. She collected a lot of very interesting friends. … She had a lot of reality that was far more interesting than fiction.”

Dundy was born Elaine Brimberg in 1921 into a prosperous New York family. Her father was a successful businessman and philanthropist but was so abusive that she left home as soon she could.

After graduating from Sweet Briar College in Virginia, where she studied acting, she moved to Europe, living first in Paris and later in London. In 1950, she met Tynan, an Oxford graduate who would soon terrorize the theater world with his brilliant and lacerating reviews for the London Observer. They were married in 1951.

Dundy worked as an actress but found only moderate success. Tynan encouraged her to try writing a novel and promised he would not read it until she was done.

The result was the semi-autobiographical “Dud Avocado,” the title of which was meant to suggest the naivete of the American woman abroad, who was tough on the outside but green on the inside.

Dundy wrote two other novels and a couple of plays before turning to biography in 1980 with “Finch, Bloody Finch” about actor Peter Finch.

Her next subject, to the horror of her sophisticated friends, was Presley, whom she did not discover until after his death in 1977. The book was considered a definitive contribution to Presley scholarship, with the Boston Globe praising it as “nothing less than the best Elvis book yet.”

Her memoir “Life Itself!” reaped the most attention with its frothy anecdotes about her glamorous public life, such as the time photographer Richard Avedon flew her and Tynan to New York, nailed them inside large crates, and presented them as birthday gifts at a party for director Mike Nichols.

There were also the shocking revelations about her husband’s desire to have sex while caning her. She submitted to his punishment several times, explaining that she stayed in the relationship partly because of his threats to kill himself if she left him and partly because of her own sickness, which she described as “the thrill of an accomplice collaborating at her own ruin.” They finally divorced in 1964. Tynan died in 1980.

In addition to her daughter, Dundy is survived by grandchildren Matthew and Ruby McBride of Los Angeles; a sister, Betty Lorwin of New York; and two nieces. Another sister, noted independent filmmaker and UCLA professor Shirley Clarke, died in 1997.