Meet Margaret Fuller, proto-Sheryl Sandberg by Lauren Kirchner @FortuneMagazine June 18, 2013, 2:42 PM EST E-mail Tweet Facebook Google Plus Linkedin Share icons A portrait of Margaret Fuller, circa 1835 FORTUNE — By now, most of us are familiar with (and perhaps tired of) Facebook FB COO Sheryl Sandberg’s best-seller Lean In: Women, Work, and the Will to Lead, and its exhortation that women be more active, confident, and vocal in their careers. Following the book’s release, Sandberg received the expected range of criticism: tone-deafness formed by personal privilege, inconsistencies in her arguments, and the discrepancies between her own life experience and the motivational sloganeering she offers her readers. There is one thing that no one could ever accuse Sandberg of, though: going halfway. Leaning in to her own campaign, so to speak, Sandberg has used proceeds from the book to launch a nonprofit organization to empower women. Sandberg has said that, as proud as she is of the book’s success, she is even more gratified by LeanIn.org’s growing community, which she says has 200,000 members. The organization centers around giving members guidance and discussion-topic suggestions for Lean In “circles,” which are “small groups that meet regularly to share and learn together — like a book club focused on helping members achieve their goals.” MORE: When the quest for a promotion turns into a talent show Encouraging the formation of “circles” isn’t an entirely novel approach, of course. From political activism to religion, guided small-group discussion is an effective way to take a broad thesis and make it more palatable and actionable. But the method is especially effective and appropriate for what Sandberg is trying to do: namely, encourage otherwise-passive women to identify their professional goals and to question and tackle obstacles in their way. A much lesser known book, published the day after Sandberg’s, tells the story of another, much lesser known pioneering feminist who shared many of Sandberg’s messages and methods. Margaret Fuller was a female journalist and critic far ahead of her time, and she is the subject of a beautiful new biography by Megan Marshall. Margaret Fuller: A New American Life celebrates Fuller’s short but eventful life and fascinating career. To the extent that Margaret Fuller’s name is known today, it is as the first editor of the Transcendentalist magazine The Dial, founded in the 1840s by Ralph Waldo Emerson and friends, or as the author of the important feminist work Woman in the Nineteenth Century in 1843. But she influenced the lives and attitudes of countless other women of her generation, first as a teacher and then, later, as an intellectual figurehead. As a child, Fuller never saw herself as being less capable because of her gender. She was raised in a strict New England household and taught by her demanding father to value her intellect. Her predilection to hold forth on literature and politics in social situations may have raised eyebrows among her classmates and prevented her from having easy friendships with girls her own age, but it served her well later in life. When she left home, matured, and made connections among other intellectuals of the day — like Ralph Waldo Emerson and the British writer Harriet Martineau — she began to envision a life as a professional writer. When her father died, Fuller resolved to provide for her family, as an eldest son would have, first as a teacher, and later as a professional book reviewer and journalist. It was as a teacher of young girls that Fuller first showed hints of the influence she would later have over her peers. She took care to teach her students lessons about historical female heroines and required readings by female authors. Instead of using traditional memorization techniques to teach her students, Fuller insisted that her students engage in conversation and practice expressing their own ideas — an unusual educational method at the time. “There is room here,” she wrote to her friend Emerson, “for a great move in the cause of education.” In time, Fuller realized that it was not just young people who could benefit from such techniques. In 1839, Marshall writes in her biography, Fuller was inspired to unite “her professional ambitions and her concerns on behalf of women.” She began a conversation group in private homes for women to discuss literature, listen to lectures on subjects like ancient mythology, and to share their opinions on women’s issues. According to Marshall, Fuller believed that “there were no capabilities belonging exclusively to either man or woman. Perhaps Margaret herself was not aware of how bold her statement was.” This boldness attracted more members to her “conversations.” The experiment was a success, both for Fuller and for her participants. One woman later wrote of her experience, “I was no longer the limitation of myself,” recalling that Fuller had “opened the book of life and helped us to read it for ourselves.” Fuller was able to charge tickets to the series, which helped her support herself for years. Fuller began to see that most women’s intellectual skills had not been developed or appreciated early in life. She saw how easily her female peers could be encouraged, and yet, how fragile that newfound confidence could be. For instance, after a year or two, when she decided to include a handful of male peers in the meeting series, the men completely dominated the conversations. Fuller joined in their debate, but she was the only woman who did. Suddenly, Marshall writes, the previously eloquent women “had turned bystanders to the men’s rambling disquisitions.” Fuller experienced some of the same types of criticisms that Sandberg would, in fact. For instance, she championed and published other female writers in The Dial, but it was a while before she felt she could acknowledge her own gender to her readers. MORE: The most powerful women in business — then and now For several years she did not sign her full name to her writings, preferring instead to let her readers think that the poet and critic S. M. Fuller (or sometimes just “F”) was a man. In one letter empathizing with a would-be contributing writer, she wrote, “I know you are plagued and it is hard to write, just so it is with me, for I also am a father.” Fuller’s Woman in the Nineteenth Century attracted a lot of attention, not all of it positive. The book mainly discussed what she saw as the inequalities inherent in the institution of marriage. Many readers bristled at her criticism of an institution she had never herself experienced, viewing Fuller as an elitist. Two of Fuller’s closest friends were the novelist Nathaniel Hawthorne and his wife Sophia Peabody. When an early version of Fuller’s treatise came out in The Dial, Peabody was not impressed. “What do you think of the speech which Queen Margaret had made from the throne?” she wrote, sarcastically, to her mother. “It seems to me that if she were married truly, she would no longer be puzzled about the rights of woman.” Critics agreed with Peabody, writing things like “No unmarried woman has any right to say any thing on the subject.” The controversy did not hurt sales, however — indeed, it probably helped — and the publisher sold out of the first run of 1,500 copies in the first week, Marshall notes. Fuller would marry, though. She was living in Europe at the time, writing columns home to the New York Tribune (“With no fanfare, she had become America’s first female correspondent,” writes Marshall) when she fell in love with a young Italian revolutionary named Giovanni Ossoli. Fuller was 38 years old when they had their first and only child. It was then that Fuller confronted the fraught and complex challenges that so many working women have faced, then and now. In 1848, while reporting on the Italian revolutions from Rome, she had to leave her infant son in the care of a nurse outside the city for weeks at a time, for safety and financial reasons. (Her husband, meanwhile, was fighting for the revolution.) Fuller would say afterward that she stayed up nights, “contriving every possible means by which, through resolution and energy on my part, I could avoid that one sacrifice,” of leaving her baby in a mountain town while she worked in Rome. “It was impossible.” She had to be at the center of the action, even though it meant she had to work alone. She was the only American journalist in Rome at the time. The family was reunited at the revolution’s end in 1850, although, sadly, none survived their return voyage to New York because of a shipwreck. Fuller was only 40 when she died. Sheryl Sandberg’s legacy is not yet written. But Margaret Fuller’s is clear. One of the women who had attended Fuller’s discussion group, Elizabeth Cady Stanton, joined Lucretia Mott in organizing the Seneca Falls Convention, one of the first and most influential steps on the path to women’s suffrage in America.