When you google "Gloria", the first item at the top of the list is Gloria Steinem. Now 85, the radical feminist who advocated “Revolution, Not Reform,” is one of the most important people of the mercurial 20th century.

In an entertaining, educational and uplifting celebration of her trailblazing journey, the American Repertory Theater in Cambridge is presenting Gloria: A Life - History. Her Story. Our Story. Under the deft direction of Diane Arbus and with a script by Emily Mann, largely focused on Gloria’s words, not potentially-biased newspaper clippings and books, the play is a mind- and heart-opening triumph.

Patricia Kalember cannily portrays the heroine's resolve and courage, humor and intelligence but, just as importantly, her penchant for distributing credit to everyone else and “thinking of herself as part of a team and part of a movement,” according to Mann.

Furthermore, the brilliant, punchy all female multi-racial cast, which helped shape the play’s dialogue in rehearsals, portrays all the roles, male and female. The voices and actions of the actresses present an illuminating dimension to the 60’s and 70’s struggle against patriarchy, as they embody a quid pro quo editor on the make for sex; a Playboy club chauvinist who approves stealing half of the bunnies’ tips; famous writers Saul Bellow and Gay Talese, who dismiss Gloria as a lightweight ornament and an empathetic doctor in London who signs a critical document for Gloria to access an abortion, among others. In addition, their female depictions, most notably, as Gloria’s mother (who she cared for until she was 17), the irrepressible Bella Abzug and the first female chief of the Cherokee Nation, Wilma Mankiller, are excellent.

The audience sits on opposite sides of the theater with the action - non-stop and expertly-paced - in the middle in Gloria’s apartment on a variety of colorful Persian rugs where Gloria narrates her evolution from the beginning when her antique-selling dad dragged his wife and daughters (she has a sister) around in a trailer for years. There are stacks of books on the floor, the shelves and on top of a low table while about a dozen audience members sit on pillows on the floor in a circle, lending an informal ambiance to the gathering.

Her mother suffers a debilitating nervous breakdown from which she never fully recovers, for two reasons, Gloria believes: she was in love with a writer better suited to her temperament but couldn’t divorce and she suppressed her own career as a promising writer in deference to her husband.

Incisive historic news footage, prominently displayed above the audience on opposing walls, is a vital and effective augment or counterpoint to the pithy stage dialogue. The women’s demonstrations are electric, while perennial villains Nixon and Kissinger are heard on tape and seen in photo stills bashing Gloria with the f-word. In another clip ABC news anchorman Howard K. Smith trashes Gloria, only to hilariously eat his words in a subsequent broadcast.

Even a protective Larry King hosts her but in a clever sleight, it is Kalember as Gloria you see opposite King, not the real Gloria.

Of all her groundbreaking accomplishments, it is arguably the establishment of Ms. Magazine which most characterizes the importance of her career. She fondly recalls how they choose the iconic, groundshifting name, their shock at the publication’s explosive impact, and how quickly it disappears from the newsstands.

Of the boxes and boxes of letters they routinely receive - some 26,000 for its inaugural edition - she reflects how important their work really was in empowering millions of women. Motivated by the magazine’s content, a former black prostitute (one of the cast) is so charged by what she reads, she attends law school and becomes a lawyer.

In one of many side-splitting scenes, a crusty Irishwoman taxi driver turns around, interrupts Gloria’s conversation and cracks: “If men could menstruate, abortion would be a sacrament.”

At 66, after innumerable partners, Gloria encounters businessman and fellow activist David Bale, whom she marries, only to lose him to lymphoma three years later.

With a kind of fond finality that concludes Act I, Gloria describes herself as an inexorable hopeaholic, much to the satisfaction and delight of the audience. Act II is a concept which succeeds brilliantly. In conversation with Mann, Gloria said: “She only wanted to tell her story if it helped other people tell their stories.”

So, Act II is a 20-minute Talking Circle, on this night featuring Natalie Martinez of Strong Women, Strong Girls. Apologizing for her shyness and tears, she explains how each year SWSG serves more than 1,200 girls from under-resourced communities in Boston and Pittsburgh with the help of 525 college women mentors. Her testimony is powerful and there follows more of the same from audience members, most memorably (and not to diminish those of a few articulate adults) of three girls in their early teens who gush how astonished they are about this woman Gloria. Why have they never heard of her, they want to know?

Gloria’s life is, well, glorious, though certainly splotched with pain and monstrous obstacles. Perhaps her path owes something to her DNA. Around the turn of the 20th century, her paternal grandmother, Pauline Perlmutter Steinem, was the chairwoman of the National Woman’s Suffrage Association.

Gloria: A Life is must-see theater and begs the question, blasphemous and hyperbolic though it might be: is she as important an American as Lincoln, FDR and Eleanor, JFK and Martin Luther King?