Barbara Howar, a best-selling author, television interviewer and gleefully nonconformist fixture of the Washington social scene, died on Friday at her home in Los Angeles. She was 89.

The cause was complications of dementia, her daughter, Bader Howar, said.

By her 30s, Ms. Howar had already become known in Washington as a successful hostess. The headline on a 1966 Life magazine article about her declared, “A Swinger Frugs Gaily Into the ‘Hostess Gap.’” (The frug, pronounced froog, was a dance. The word swinger was used more broadly then.) Early newspaper articles identified her as Mrs. Edmond N. Howar, in the society-column style of the period. Her husband at the time was a prominent Washington real estate developer.

But it was “Laughing All the Way,” her irreverent 1973 memoir, that put Barbara Howar on the map.

In a decade that worshiped candor, “Laughing All the Way” spent months on The New York Times best-seller list. People magazine called its author “one of the most uninhibited, outspoken women in Washington.” (She once wore pajamas to an embassy gala.)

And the book put her on television. There she was on “The Tonight Show,” chatting with Johnny Carson about a minor bad-boy-on-staff scandal within the Jimmy Carter administration and suggesting that “the media kind of controls everything.”

The next year she was interviewing the singer Anita Bryant on CBS about Ms. Bryant’s campaign against homosexuality. At one point Ms. Howar asked, “Where is your human sense of decency and fairness to people who are different from you?”