The poster seemed innocuous enough, but its timing was atrocious. At the height of the women’s movement in the early 1970s there was one advertisement that enraged women so much that they decided to picket the company responsible. The ad, for Olivetti typewriters, showed a young blonde woman seated at her typewriter, her long legs crossed, her red lips making a seductive pout for the camera.

“The typewriter that’s so smart,” ran the caption, “that she doesn’t have to be.”

One of the women who joined the picket was young, blonde and attractive like the girl in the poster. Two hours into the meeting she admitted that she was indeed the pretty young thing in the ad. The women around her were jubilant. “You see,” they told her. “Even the women in the ads don’t like them.”

The model in question was Shere Hite who, proving that she was not so dumb, went on to write a bestselling study of women’s sex lives, The Hite Report on Female Sexuality.

It is the 30th anniversary of the American’s earth-moving announcement in The Hite Report that she had discovered what women liked in the bedroom. Her message was that women didn’t need men to find sexual satisfaction. Hite’s book, containing frank interviews with scores of ordinary people, sold more than 20m copies. The reaction of men was not ecstatic; some felt redundant. Playboy, for whom this least conventional of feminists had modelled, dubbed her book the Hate Report.

Hite became a famous feminist, propelled into a galaxy inhabited by Betty Friedan, Gloria Steinem, Andrea Dworkin and, later, Naomi Wolf.

With such success, Hite could have lain back and thought of her bank balance. Instead, she followed it up with a string of socio-sexology books — The Hite Report on Men, among others. Each time, more detractors lined up against her. They attacked her for basing her findings on only 4,500 women, arguing that the women she chose were “self-selecting”, skewing her research methodology. Dissatisfied with their sex lives, they argued, they were bound to portray a life of misery behind the bedroom door.

Even Friedan castigated one of her later studies, The Hite Report on Women and Love, as “one long whine”. So, as her latest offering is published, The Shere Hite Reader, she is braced.

Conventionality is as alien to her as orgasms were, in her view, to 1950s housewives. Now 63, with golden curls and tight porcelain skin, she looks like a woman for whom old age is years away and sex remains more than an academic interest. Last week she flew to Britain to lecture at London’s ICA on global terrorism and, of course, sex.

Her trip breaks a long public silence. For years she was reluctant to speak because she felt unable to defend aspects of the sexual revolution she helped to unleash. This week she will defend our attempts to foster western values in Iraq, even offering mild praise to George W Bush for “pointing out that women have equal rights”. She will attack the resurgence of religion, Christian and Islamic, which she fears threaten to claw back the gains of feminism.

Hite sees herself as a martyr to feminisim. The Hite Report created such a rumpus in America that she claims she had to leave. She seems rather to enjoy her heroic exile status. “I went back recently to see my family,” she said last week, “and, by the way, they still don’t talk about it.” With Hite in the family, that is some achievement: she talks about “it” an awful lot. “I brought it up finally.” Her folks reacted, she says, “by avoiding using any of the words”.

“Their view was if men haven’t understood the female orgasm — not that they would use that phrase — that is a woman’s own fault. And they insisted, ‘That was never a problem for me’. They were brought up to be good girls and never talk about these matters.”

Born plain Shirley in Missouri in 1942, Hite’s upbringing saw her shuttled between parents and grandparents. Hite’s teenage mother, also Shirley, was the high school sweetheart of her father, Paul Gregory, a second world war serviceman and livestock supervisor. After three years of marriage, her parents divorced and her mother married Raymond Hite, a truck driver, but that marriage too ended after a couple of years.