Tits are back, baby. “Breasts,” a show of tits throughout the ages, just opened at the ACP Palazzo Franchetti in Venice for the Biennale. This comes on the heels of “Darker, Lighter, Puffy, Flat” at the Kunsthalle Wein, which examined the significance of breasts, from the maternal to the sexual to the biological. Last year, there was also “Boobs in Art” at Berlin’s DITTRICH & SCHLECHTRIEM, a comprehensive exhibition of 100 artists grappling with mammary glands that included a painting by Paula Modersohn-Becker from 1906, considered the first self-depicted nude by a woman.

Sarah Thornton’s new book, Tits Up: What Sex Workers, Milk Bankers, Plastic Surgeons, Bra Designers, and Witches Tell Us About Breasts (336 pages; Norton), would seem to come at an auspicious time. This flurry of exhibitions surely indicates a larger trend. People are sensing there is more to this body part, which often gets overly sexualized, made into a joke, or both, than previously thought. This flies in the face of assumptions made by many, including feminists, that breasts belong to first-wave feminism, or that most conversations about it begin and end with the male gaze, or even that titties haven’t been an interesting subject matter since artists like Valie Export encouraged passersby to feel her breasts inside a cardboard “TV set” in 1974. (“The bar for saying something new about tits [is] fairly high,” as one editor told me.)

Just because mammaries, which evolved over 300 million years ago, received some critical attention in the ’70s, doesn’t mean they are a passé topic. Even if breasts have not changed much in the past fifty-plus years, culture has. The increased visibility of trans and nonbinary people has brought about much-needed dialogue around gender, particularly as it relates to our top halves. As artist, psychologist, and witch Edgar Fabián Frías told me, “Trans people are actively problematizing and critiquing conventional narratives surrounding breasts.” It’s a sentiment Thornton echoes in her book: “Gender is ever more about self-presentation and the visible top halves of our bodies.”

Additionally, there is the global dominance of social media with its algorithms that censor female nipples, while making arbitrary distinctions between fine art and porn. “Make art about gender and sexuality and use the body…Your ideas are suppressed,” tweeted OONA, an anonymous performance artist who frequently uses her breasts in her work. This harks back to earlier conversations around the policing of breasts (and by extension women) and the male gaze. But the fact that there are 4.8 billion social media users—approximately 60 percent of the global population, who spend, on average, 145 minutes a day on various platforms—has given this conversation new urgency.

Trans visibility and social media censorship are not new. But recent anti-trans and anti-women’s rights legislation combined with our unprecedented amount of online activity has placed both issues center stage like never before. And they’ve taken their controversial bosoms along with them. As a result, it’s not so much that titties are back (they never went anywhere). It’s that the festering regarding all things unspoken about tits has reached a head.

Thornton has a history of being prescient. Her earlier book, Seven Days in the Art World, which covers the economy and ecology of the high-end art world, was published in 2008. At the time, the art world, a fairly esoteric and elitist field, was just starting to enter mainstream consciousness—becoming synonymous with fashion, media, and celebrity. The international success of Thornton’s book, which was translated into twenty languages, ushered in and solidified this movement. And now she appears to be doing it again, albeit with a much more high-stakes and arguably more important topic.

In her very personal introduction, Thornton gives the reader background on her own tits. As an undergrad art history major, Thornton had seen thirty thousand years-worth of topless Venuses and Madonnas with little critical airtime going to their top halves. And she hadn’t given much more scrutiny to her own top half over the years. But in 2018, she underwent a double mastectomy, which spurred her to think more about them. “How is it we look at breasts so much but reflect on them so little?” she asks. This was a question that felt especially poignant for me as a new, breastfeeding mother. Before reading Tits Up, I hadn’t stopped to think about the significance or extraordinariness of my own life-sustaining breasts. Instead, I’d internalized the messaging that breasts, when they weren’t actively engaging or subverting the male gaze, just weren’t that interesting.

There is so much new and illuminating information about breasts in Tits Up, which explores the worlds of five different breast experts—all of which deeply respect the power embodied in breasts—that it would be a folly to try to list it out here. However, one of the most striking pieces of information has to do with Carl Linnaeus, the botanist, zoologist, and physician who coined the terms Mammalia, for the mammal kingdom, and Homo sapien, for the human species. Linnaeus was the eldest son of a Lutheran minister and almost became a priest before becoming a doctor. He was actively against education for women, including his own daughters. Thornton makes the point that this seemingly neutral nomenclature is anything but. Homo sapiens means “wise man” in Latin. And only women have mammary glands. “With Linnaeus’s reorganization of the animal world, breasts became visual evidence of women’s intellectual inferiority and innate subservience,” Thornton explains. It’s a puritanical legacy that continues to haunt our collective consciousness. It can be seen in the overturning of Roe v. Wade, in the bills that exclude trans people from updating their driver’s license, holding public office, or accessing a public restroom, and in the algorithms that see a topless man as harmless but a topless woman as pornography.

This insight into Linneaus’s naming system, which is hinted at in the introduction when Thornton reflects on her breastfeeding experience, is shared in the fifth and final chapter. It comes right after Thornton has stripped off her top to give a talk to a group of witches in the woods. And when it comes, it feels climatic: the book’s great reveal. It’s depressing information, to be sure. But it’s also a reminder that breasts are powerful. Breasts are threatening. They are not silly or sexy body parts that simply bounce up and down (breasts actually move in a figure-8 pattern, another fact I learned from Tits Up). They are the body part around which much oppression has hinged, and for that reason, and many others, are deserving of our utmost respect.

Thornton honors her subject throughout Tits Up through her meticulous research and critical contemplation. But she also honors them through art. She may not be writing about art in the same way she did in Seven Days, but Tits Up is full of reproductions of photographs, sculptures, and paintings of titties. There is Catherine Opie’s Self-Portrait Nursing (2004), which depicts the butch LGBTQ+ icon breastfeeding her son. There is Micol Hebron’s “This is a male nipple,” a protest pasty from a photo of a male nipple that went viral on Instagram (also included in the exhibition “Boobs in Art”). There is Clarity Haynes’s torso portrait painting of a topless Thornton. And there are many, many other examples.

The reproductions may not be Phaidon worthy, but the curation is as good as any museum exhibition in Venice, Wien, or Berlin. The art here is also more precious than anything referenced in Seven Days, because it is personal to Thornton. The “Wave Goodbye to the Patriarchy” handkerchief made by a witch from the witches’ retreat, the photographs of Annie Sprinkle’s Bosom Ballet done to a Blue Danube waltz, the painting by Chitra Ganesh of a three-breasted woman with eyes for nipples: these are all artworks made by people Thornton has met, either literally or figuratively, along the way of her healing journey. For that is how I read Tits Up, as a healing journey. In the introduction, plastic surgeon Carolyn Chang is quoted as telling Thornthon: “’A mastectomy is an amputation. Losing a body part is a severe trauma. Amputees wear prostheses to make them feel normal … But it takes time.’ ” Tits Up might read like an ethnographic dissertation about breasts with the thesis that words matter. And they do. But just underneath that is a softer, more subtle message that art heals—as do encounters with the spectacular array of souls out there in the wide and varied world.

Mieke Marple is an artist and writer living in Los Angeles. A contributor to ZYZZYVA, she has also written for The Huffington Post, Lit Hub, ArtNews, and Artsy, among others.