Barbara Walters tells all in autobiography

The longtime television interviewer was in her 10th-floor office at ABC on a recent afternoon, talking about her new autobiography, "Audition."

In it, Walters spills about her guilt-ridden relationship with her mentally disabled older sister, her father's attempted suicide, her daughter's turbulent adolescence, her three failed marriages and various run-ins with male colleagues.

"When I look back now I think, I don't know -- should I have told so much?" she said. "But if you're going to be honest, you're going to be honest."

Perhaps the most revealing aspect of the 612-page book -- aside from her confession of an affair with a married African American U.S. senator in the 1970s -- is Walters' admission that she was long haunted by deep-set insecurities.

They dogged her after she was named the first co-host of NBC's "Today" show; when ABC lured her away to be the first female co-anchor of a network evening newscast; even as she hopscotched the globe, interviewing foreign leaders.

"No matter how high my profile became . . . my fear was that it all could be taken away from me," she wrote.

After more than four decades on the air, during which time she's interviewed 30 heads of state, every president since Richard M. Nixon and countless celebrities, that anxiety has finally subsided.

"It's about time," Walters said.

The 78-year-old broadcaster (an age she refuses to confirm), had been up since dawn to guest host "Good Morning America" and then taped two episodes of "The View" before lunch. Her makeup was immaculate, her blond hair perfectly coiffed. She was dressed smartly in a taupe suit accented with gold jewelry.

"I have a lot of energy," said Walters, but she's contemplating retirement. "I don't want to climb any more mountains."

She started working on her autobiography after leaving "20/20" in 2004, in part to let people know that she has "not had a perfect life by any means." (Walters will be in town for three book signings next week, including one Monday at Saks Fifth Avenue in Beverly Hills.)

It isn't a leap, she admits, to connect her lifelong worries about being accepted to an insecure childhood. The youngest daughter of a nightclub impresario who gambled, Walters was a "somewhat lonely child" acutely aware of her family's precarious situation. Further complicating her home life was the condition of her older sister, Jacqueline, whom Walters both loved and resented.