IN HER THOSE-WERE-THE-DAYS-MY-FRIENDS essay “Journalism: A Love Story,” Nora Ephron famously wrote of moving up the pink ladder at Newsweek, from mail girl to clipper to checker, that “It was a given in those days that if you were a woman and you wanted to do certain things, you were going to have to be the exception to the rule.” Ephron’s recollection of hitting the newsmagazine’s impermeable glass ceiling is recounted as matter-of-factly as an encounter with a bad bowl of soup: Once she realized that she would never get to be a writer at the magazine, she simply moved to a job at the New York Post, where she had four bylines in her first week. In typical — that is to say, delightfully decontextualized — fashion, the essay acknowledges, but then shrugs off, a deeper awareness of that workplace’s structural inequity. The first time I read it, I wondered whether Ephron’s many cohorts at the clip and research desks were so at ease with those inbuilt limitations. As it turns out, many of them weren’t. Lynn Povich’s new book The Good Girls Revolt more than picks up Ephron’s slack, delving into what it took for one group of women to interrogate, fight, and start to correct the inequity.

In 1970, Povich was part of the first-ever class-action sex-discrimination suit, filed by 46 female employees at Newsweek. The women were clippers, researchers, and, in a few cases, reporters. If they expressed interest in writing, they were promptly rebuffed with the edict “Women don’t write at Newsweek.” But even those who didn’t necessarily aspire to the top of the masthead realized that the subservient role of women at the magazine wouldn’t change unless they forced a few hands. Their EEOC suit stated that the women had been “systematically discriminated against in both hiring and promotion and forced to assume a subsidiary role”; with strategic irony, it was filed the same day that Newsweek’s cover story on the feminist movement, titled “Women in Revolt” hit newsstands.

A lawsuit was an unprecedented move, and, for the women involved — self-identified “good girls” of breeding and manners, many of them graduates of Seven Sisters colleges like Vassar and Radcliffe, and none previously possessed of radical urges — a revelatory one. (Povich herself, the daughter of sportswriter Shirley Povich and sister to the soon-to-be media macher Maury, recalls writing to a friend that becoming a journalist would be her “first exposure to a real challenge.”) Though the burgeoning women’s movement was in the air, its heady sisterhood-is-powerful scent hadn’t yet reached many women who, particularly in the high-pressure, big-ego work of New York City media, had been taught to view each other as competition. As Pat Lynden, a reporter who signed on to the suit in its infant stages, recalls in the book, “Women just didn’t trust each other. We didn’t talk about our salaries. We fought over the bones like crazy.”

And what little professional camaraderie there was didn’t cross race lines. Though there were black women working as researchers at Newsweek, they declined to join the suit, a fact that was both frustrating and understandable to Eleanor Holmes Norton, the black ACLU attorney who helmed the case. “We were in the throes of the Civil Rights Movement,” Norton...