One of the Janes persuaded him to teach her. Within months she had learned the procedure and soon trained others. The Janes were able to cut ties with back alley abortionists, dispense with blindfolds and lower the price to $100, with poor women paying less.

Only about four of the 100 or so women who joined Jane ever became skillful enough to perform surgical abortions. The others mostly answered calls, found safe apartments and assisted by sterilizing instruments and changing bedsheets. They acted as counselors, chauffeurs, nurses. No woman is known to have died at the hands of the Jane abortion providers. One Chicago obstetrician, who had agreed to provide follow-up visits to Jane patients, attested that these practitioners had a safety rate roughly the same as that of the legal clinics then operating in New York.

In 1972, the police raided an apartment where Jane operated. Three patients waiting for abortions were taken to a hospital. Seven Jane members were arrested, among them a high school English teacher, several housewives with young children, and a student who was about to adopt a baby. In the police van, one removed from her purse a stack of 3-by-5 cards with contact information for women who’d called for help. They ripped off the corners with the patients’ names and addresses, and swallowed them.

The “Abortion Seven” were indicted. But before their case went to trial, the Supreme Court legalized abortion in the 1973 Roe v. Wade decision. The charges were dropped. Jane disbanded.

Ms. Booth is now an organizer with the consulting group Democracy Partners. “We will never go back underground,” she said. “Women and men assume that abortion will be available, that women can determine when or whether to have a child. That change is enormous.”

And yet abortion restrictions are once again so widespread that some activists are preparing for a modern-day service like Jane. Elizabeth Ziff, a member of an “underground feminist group,” is one of them. “They — this administration — are coming for all of it, the morning-after pill, birth control, abortion, all of it,” said Ms. Ziff, who is also a singer and guitarist for the feminist rock band Betty. “Women will suffer if we aren’t willing to take radical steps. And that includes learning how to perform abortions.”

But the situation for women seeking abortions and the activists who might help them is today far different from that of the Jane era. Charlotte Taft, a former director of the Abortion Care Network, said no one should “unravel a coat hanger,” especially now that “medication can create abortion far into a pregnancy.”