Phillips, who went by the pen name Abigail Van Buren, succumbed after a decade-long battle with Alzheimer's disease in Minneapolis, her syndicate, Universal UClick said in a statement.
"I have lost my mother, my mentor and my best friend," said daughter Jeanne Phillips, who took over writing her mother's column in 2002 after the she was diagnosed with the degenerative condition. "My mother leaves very big high heels to fill with a legacy of compassion,commitment and positive social change. I will honor her memory every day by continuing this legacy."
Phillips began writing Dear Abby in 1956 for the San Francisco Chronicle a bored housewife looking for something to do with her time, ultimately growing her readership to more than 100 million in syndication.
Known for her tart, unflinching style, Phillips became the best friend and big sister for millions through her columns. She championed women's rights, minorities, education and more.
DEAR ABBY:About four months ago, the house across the street was sold to a "father and son"--or so we thought. We later learned it was an older man about 50 and a young fellow about 24.
This was a respectable neighborhood before this "odd couple" moved in...
Abby, these weirdos are wrecking our property values! How can we improve the quality of this once-respectable neighborhood?
UP IN ARMS
DEAR UP: You could move.
In 1987, "Dear Abby" tested the columns appeal by asking readers to send in postcards or letters (no names required) if they had ever cheated on a partner or spouse. Nearly a quarter of a million people wrote in over three months. And in 1992, more than 300,000 readers responded to a survey asking people to share where they were when President John F. Kennedy was assassinated.
Her twin sister, Eppie Lederer, more commonly known as advice columnist Ann Landers, with whom she had a contentious relationship. The two publicly reconciled, but were said not to get along for most of their lives.
Jeanne Phillips began sharing column duties with her mother in the mid-1990s, and took over full time in 2002, continuing to write under the byline Abigail Van Buren.