She wrote under the name Abigail Van Buren, plucking the name Abigail from the Bible and Van Buren from American history. Her column competed for decades with that of Ann Landers, who was none other than her twin sister, Esther Friedman Lederer (she died in 2002.) Their relationship was stormy in their early adult years, but they later regained the closeness they'd had growing up in Sioux City, Iowa.
Carolyn Hax, who writes her own syndicated advice column, feels that one can't speak of one sister without the other, so influential were they both, and at the same time.
"Any of us who do this owe them such a debt," she said. "The advice column was a backwater of the newspaper, and now it is so woven into our cultural fabric. These columns are loved and widely read, by people you wouldn't expect. That couldn't have happened without them."
In a time before confessional talk shows and the nothing-is-too-private culture of the Web, the sisters' columns offered a rare window into Americans' private lives and a forum for discussing marriage, sex and the swiftly changing mores of the 1950s, '60s and '70s.
The two columns differed in style, though. While Ann Landers responded to questioners with homey, detailed advice, Abby's replies were more flippant and occasionally risqué, like some collected for her 1981 book "The Best of Dear Abby."
Dear Abby: My boyfriend is going to be 20 years old next month. I'd like to give him something nice for his birthday. What do you think he'd like? — Carol
Dear Carol: Nevermind what he'd like, give him a tie.
Dear Abby: I've been going with this girl for a year. How can I get her to say yes? — Don
Dear Don: What's the question?
Jeanne Phillips, who took over the column in 2002 after a few years of sharing the byline, recalled in a telephone interview Thursday her mother's response to a woman who wrote in detail of how many drinks she'd shared with her date one night. "Did I do wrong?" the woman wrote, in the daughter's retelling.
"Probably," her mom responded.