Katie Roiphe is famous for being very sure of herself, for stating unpopular positions with great force and for not caring if people hate her. In her own words, she is “ferocious.” Her narrative persona is “a tank.” In her latest work, “The Power Notebooks,” she seems as surprised as we are to find herself taking a break from the role of steel-sided contrarian.

A hybrid of memoir and literary criticism, the book (on sale March 3) proceeds in brief, loosely connected chapters. Each contains a series of paragraphs reminiscent of Jenny Offill’s autobiographical fiction or Maggie Nelson’s essays. In daily, pre-dawn sessions, Roiphe tells us, she sat down with a notebook and forced herself “to do things I otherwise never let myself do: admit weakness, give up control, acknowledge doubt, have no idea where I am going.”

The first topic is her first marriage, an emotionally abusive relationship she describes in detail. In one scene, her husband berates her so furiously that their baby could not eat and her neighbors called their building’s management company. But even as she’s saying it, Roiphe wants to take it back. “The word abusive strikes me as impossible, not just because of what it says about H. but because of what it says about me.”

She moves on to debrief other relationships with men and with female friends, contextualizing these with stories from the lives of other female writers — Simone de Beauvoir (proud to be wholly submitted to the faithless Sartre), Mary McCarthy (had to ask her husband for a nickel to make a phone call), Sylvia Plath and Edith Wharton (both gutted and filled with self-loathing by a partner’s infidelity.)

How does this work, she wonders. These women are “strong in public, weak in private. Is there a particular kind of abjection that some of us are drawn to, participate in, possibly romanticize, even though nothing about our external lives necessarily suggests it? If so, is there a way out of it?”

Roiphe moves toward the way out with a quote from Chris Kraus’s novel “I Love Dick”: “Why does everybody think that women are debasing themselves when we expose the conditions of our own debasement?”

What these women are doing, it turns out, is reframing and redeeming their “debasement” or “abjection” by making art about it. In these notebooks, Roiphe is trying it for herself: admitting weakness and shame as a way of working toward strength.

Turns out, she’s not completely sold.

She writes with annoyance of her students’ admiration for writers like Zadie Smith, Leslie Jamison, Roxane Gay and Joan Didion. These writers achieve “relatability” — Roiphe seems to hold the very word at arm’s length — by showing weakness, softening their edges, by sounding “not totally pulled together.” To achieve relatability, she explains, you might “confess that you are drinking too much, say, or crying in the street, or stylishly neurotic a la Joan Didion or suffering with an eating disorder or struggling with depression.”

She goes on to quote specific “I-am-a-mess moments” from these writers and others. Jamison ate food from the trash. Gay was so lacking in confidence that she puked before teaching. Every time she got drunk, Mary McCarthy started blathering about the czar. (Oh, Mary, not again.)

Everyone is a mess, Roiphe grants. “The question is whether you want to announce or billboard it in your writing.” At this point, I felt confused. Isn’t this whole book Roiphe’s I’m-a-mess moment? She dips her toe in the water — then runs back to the beach. Perhaps these very contradictions are part of the freedom she’s allowing herself.

I happened to read Roiphe’s book immediately after another new memoir, “Brother & Sister,” by Diane Keaton. Keaton is our cultural avatar of the I’m-a-mess moment. She even designed its wardrobe. In her third memoir, there’s no tentative toe-testing. From page one, Keaton dives deep into a pool of regret about her relationship with her mentally ill younger brother, Randy Hall. “For many years, when we were young, I saw Randy as an inexplicable burden. He was a nuisance, a scaredy-cat, and a crybaby.” Though the two were close in childhood, Randy was a slow-motion failure to launch. After a brief marriage and career working for their dad, Randy ended up spending his time collaging, writing poetry, drinking and indulging in fantasies of violence.

Until recently, Keaton was too absorbed in her career to pay much attention. She was on set filming “Reds” when Randy tried to gas himself in the garage. Now their supportive parents are gone, the siblings are in their 70s, and Keaton is rubbing Hall’s feet in his bedroom at a memory-care facility, reading her way through her mother’s journals and her brother’s poetry.

It’s not only her poor performance as a sibling that Keaton shares with us. Just as Roiphe has a chapter devoted to “More Bad Things About Me In Print,” Keaton explains why success is “a confusing dream come true.” She shares her mother’s discomfort with the skewed representation of their family in the movie “Annie Hall.” (The family’s last name is Hall.) Though she thought Christopher Walken was pretty good as the Randy character, Colleen Dewhurst as Mom was “not a high spot.” She quotes Roger Ebert commenting on her film “I Will … I Will … For Now”: “Diane Keaton is so painfully sincere, we’re not even sure some scenes are supposed to be funny.”

Her reaction to this blow? She took her cue from Randy, who had recently gotten some negative feedback on his artistic endeavors. Like her brother, Keaton threw herself into collaging and journaling. She even shares a few of the “short, depressing entries” she wrote at the time: “Woody has taken to buying cigarettes.” “Art Linkletter’s daughter Diane jumped out a window.” “My face is open to deceit, deception ... and plain old apathy.”

Keaton also traces back to Randy what she recognizes as a career based on the projection of harmlessness. “My brother and I have done a good job of selling our brand of the innocuous encounter,” she writes. “I ask myself if my early disdain for his ever-ready smile was based on the fact that I copied it.”

After reading Katie Roiphe, all of this — the openness about her failures with her brother, her negative reviews and gloomy diary entries, the sharp-edged analysis of her own appeal — seems not just a bid for relatability (perhaps just another way of saying human connection), but an exercise in the redemptive power of admitting weakness and error.

A big chunk of contemporary memoir is devoted to the author figuring out where she went wrong in this or that phase of her life. I say “she” because women dominate this field; we are generally better at it than men, who rarely master the power move of vulnerability. One notable exception might be Hillary Clinton, who just couldn’t pull it off. As she wrote in her memoir, quoted by Roiphe, “What could I do to be ‘more real’? Dance on a table? Swear a blue streak? Break down sobbing? That’s not me.”

Breaking down sobbing, at least in print, is a good thing. We embrace it. We admire it. You could even say we need it — as an affirmation of and solace for the darker daily experiences of our lives.

Marion Winik, a professor at the University of Baltimore, is the author of numerous books, including “First Comes Love,” “The Lunch-Box Chronicles” and, most recently, “The Big Book of the Dead.”

THE POWER NOTEBOOKS

By Katie Roiphe

Free Press.

256 pp. $27