Norma Swenson was working to educate women about childbirth, championing their right to have a say about how they delivered their babies, when she met the members of the collective that had put out the first rough version of what would become the feminist health classic “Our Bodies, Ourselves.” It was around 1970, and she recalled a few of the women attending a meeting she was holding in Newton, Mass., where she lived.

It did not go well. One of them shouted at her, “You are not a feminist, you’ll never be a feminist and you need to go to school!”

“I was stricken,” Ms. Swenson remembered in a StoryCorps interview in 2018. “But also feeling that maybe she was right. I needed to know more things.”

She did, however, know quite a bit about the medical establishment, the paternalistic and condescending behavior of male doctors — in 1960, only 6 percent of incoming medical students were female — and the harmful effect that behavior had on women’s health. She had lived it, during the birth of her daughter in 1958.

Despite the initial tension — the woman who had berated Ms. Swenson felt her activism was too polite, too old-school — the members of the Boston Women’s Health Book Collective, as they called themselves, invited Ms. Swenson to join their group. She would go on to help make “Our Bodies, Ourselves” a global best seller. It was a relationship that lasted for the next half-century.

Ms. Swenson died on May 11 at her home in Newton. She was 93.

The cause was cancer, her daughter, Sarah Swenson, said.

It was during a women’s liberation conference in Boston in 1969 that a small group began sharing stories of their fraught experiences with doctors. They told of their frustration with the sexism of the medical establishment and of how confounded they were by the lack of knowledge they had about their own bodies. So they set out to learn for themselves, and in so doing they began to assemble a candid and humane encyclopedia of women’s health — by women, for women.

In 1970, the New England Free Press published their first rough version. It was an immediate underground success, with some 225,000 copies eventually sold. The publisher couldn’t keep up with the demand.

Ms. Swenson joined the group in 1971, when commercial publishers were courting the group’s members. After Simon & Schuster published the book in 1973, much gussied up and expanded, it became a juggernaut.

It covered topics that were then considered unmentionable and, in the case of abortion, illegal: sexuality, masturbation, abortion and birth control. There were chapters on body image, rape and self-defense; on heterosexual and lesbian relationships; on childbirth and its aftermath; and, in later editions, on menopause. There were detailed illustrations — including six variations of hymens — and photographs, including a helpful how-to for viewing one’s own vagina with a mirror.

When The New York Times’s chief book critic, Christopher Lehmann-Haupt — a man! — reviewed it, he explained his rationale for giving himself the assignment.

“I learned a great deal from this book that I did not know before, or had somehow forgotten,” he wrote. “And if the authors are correct in their belief that one of the major reasons why men oppress women is because ‘of the male fear and envy of the generative and sexual powers of women’ — and I think they are — why, then, it will do no harm at all for men to read ‘Our Bodies, Ourselves’ and expend a little rational thought on these powers.”

The book revolutionized how women’s health was discussed, and it quickly became a cultural touchstone. Reading it — often under the covers — was a rite of passage for many young women, who nicked it from their mothers’ bedside tables. More progressive moms gave it to their daughters in lieu of “the talk.”

Barbara Ehrenreich called it a manifesto of medical populism. The Moral Majority deemed it obscene. It even had a cameo in “Heartburn,” Nora Ephron’s 1983 revenge novel about the breakup of her marriage.

But the book was always a labor of love. And as the royalties poured in, the Obos, as they called themselves, used the money not to pay themselves but to create a nonprofit that made small grants to women’s health groups.

In 1977, Ms. Swenson and Judy Norsigian, another core member of the collective, teamed up for a tour of 10 European countries to meet with women’s groups who were putting together their own versions of “Our Bodies, Ourselves.” Ms. Swenson would later help to oversee the international editions and adaptations, and would lecture around the world, particularly in developing countries.

“Norma was always committed to an intersectional approach,” Ms. Norsigian said. “She made sure the activism could fit people’s lifestyles. How they could do things with limited resources. How to tailor the work to specific communities in less industrialized countries. She helped breastfeeding support groups in the Philippines, for example, and met with a doctor in Bangladesh who was advocating for indigenous production of essential drugs.”

“Feminism,” Ms. Swenson once told a group of doctors, “is just another name for self-respect.”

Norma Lucille Meras was born on Feb. 2, 1932, in Exeter, N.H., the only child of Halford Meras, who owned the town’s furniture store, and Nellie (Kenick) Meras, who worked as the store’s bookkeeper.

When she was 9, the family moved to Boston. She attended the prestigious Girls’ Latin School (now Boston Latin Academy), graduating in 1949 and studied sociology at Tufts University. She graduated in 1953 and, three years later, married John Swenson, a decorated World War II pilot — he was a member of the 100th Bomb Group of the Eighth Air Force, also known as the Bloody Hundredth — who worked in insurance and for the Post Office.

It was her daughter’s birth that had made Ms. Swenson an activist. She wanted to deliver the baby naturally, without medication. Her decision was such an anomaly that residents at the Boston Lying-In Hospital gathered to watch her labor. It went swimmingly.

But Ms. Swenson, who was in a 12-bed ward, was surrounded by women who were suffering. They were giving birth according to the practices of the era: with a dose of Scopolamine, a drug that induced so-called twilight sleep and hallucinations, followed by a shot of Demerol, an opioid.

She remembered the women screaming, trying to climb out of their beds, calling for their mothers and cursing their husbands before being knocked out by the Demerol, their babies delivered by forceps.

It was barbaric, she thought. “These women weren’t being helped,” she said in 2018, “they were being controlled.”

She became president of the Boston Association for Childbirth Education, which focused on natural childbirth, in 1964, and later served as president of the International Childbirth Education Association. She earned a master’s degree in public health from Harvard in 1973.

Mr. Swenson died in 2002. Ms. Swenson’s partner for the next decade and a half, Leonard van Gaasbeek, died in 2019. Her daughter is her only immediate survivor.

For most of her life, Ms. Swenson traveled the world as an expert on reproductive rights and women’s and children’s health, advising women’s health groups and helping to connect them with policy and grant makers. She taught at the Harvard School of Public Health and served as a consultant to the World Health Organization and other groups.

“Our Bodies, Ourselves,” last updated in 2011, has sold more than four million copies and been translated into 34 languages. The nonprofit behind the book, which provides health resources to women, is now based at Suffolk University in Boston.

“It’s not that things have so dramatically improved for women,” Ms. Swenson told The Times in 1985. “But they’d be much worse if it were not for the pressure of the women’s health movement. We are a presence now that cannot be made to disappear.”

She continued: “Women’s voices are being heard, speaking about their needs and their experiences, and they are not going along with having decisions based simply on what the medical profession needs or what the drug industry needs. I find that enormously exciting.”