Long after Betty Friedan wrote “The Feminine Mystique,” she once was a guest at the Gridiron Dinner, a white-tie affair of senior Washington journalists attended by the president and other dignitaries. She had never slowed down. In the midst of the dinner, she marched up to the head table, greeted first lady Nancy Reagan, and urged her to support the Equal Rights Amendment.

At a lawn party the next day, she accosted Chief Justice Warren E. Burger and argued with him about some pending case involving women’s rights. During that weekend, a dozen or so middle-aged women came up to her and said the same thing: “You changed my life.”

Betty Friedan’s 1963 best-seller grew out of her own experience in the 1950s. She had been a bright major in psychology at Smith College and was on her way to a doctorate when her boyfriend at the time, threatened by her success, pressured her to turn down a prestigious fellowship.

Later, as a suburban housewife with a husband and three children, she wrote freelance articles for women’s magazines. But she felt vaguely guilty at working outside the home. Politicians, advertisers and the entire national culture taught that woman’s place was in the home and that she should be satisfied with doing the housework, raising the children and keeping her husband happy and satisfied.

The turning point came when she conducted a survey in 1957 for the 15th reunion of her college graduating class. She expected to refute a current belief that higher education interfered with success as a wife and mother. To her surprise, her classmates, instead of expressing satisfaction, voiced a “nameless, aching dissatisfaction,” which she came to call “the problem that has no name.” To describe the myth of suburban women’s domestic fulfillment, she coined the term “the feminine mystique.”

Her book, which has sold more than 3 million copies, was a prime factor in overcoming ambitious women’s guilt and opening the way for them to enter fields including business, medicine, law and military service.

Her later books and articles focused on the need for husbands to share in keeping house and raising children. And, as always, she defended a woman’s right to remain a homemaker if she chooses to do so.

Still later, Ms. Friedan dealt with aging. She took gerontologists to task for going to nursing homes to study older people. She called those institutions places to die and campaigned for active, constructive life at home after retirement.

Last Saturday, on her 85th birthday, after several years of failing health, and after practicing what she preached right to the end, she died in her own home.