A smart new history takes boobs seriously.

This review is being published in partnership with Jezebel.com.

I don't have any children yet, so my breasts are still more aesthetic than functional. I mostly use them as a food shelf, a cellphone case, and an in-flight pillow. When I was young and single and had less self-esteem, I used to joke that my breasts were "all I had" (good one, unhappy baby self!), but now that I'm older, I don’t have to rely on them to feel beautiful—for the time being, they're just parts of me that fill my clothes and make my back hurt and, sure, make me feel pretty sometimes. I just don’t think about them that much anymore. Thanks to Breasts: A Natural and Unnatural History, a surprisingly emotional book by Florence Williams, though, that's all changing. All of a sudden I can't stop thinking about my breasts. Because it turns out they are total jerks.

In Breasts, Williams, a contributing editor for Outside magazine, attempts to offer a comprehensive social, cultural, medical, and scientific history of the human breast, a la single-word-titled best-sellers like Cod or Salt or Stiff—though not, alas, Balls. (In an act of one-word-wonder solidarity, Stiff author Mary Roach blurbed Breasts, citing Williams' "double-D talents.") Though that genre of sweeping, single-topic histories can wind up feeling hasty and reductive (it's hard to write the history of one thing without touching on the history of all other things), Williams’ writing is scientifically detailed yet warm and accessible. She also stays firmly away from the juvenile (BOOOOOOOOO!!!) and isn't afraid to delve into her personal life, making Breasts a smart and relatable, if occasionally dry, read.

Williams' journey begins when, alarmed by a news article about toxins in breast milk, she decides to get her own milk tested. And, surprise! It's packed with toxins—specifically, chemical flame retardants—that Williams is funneling directly into her baby. ("Well, at least your breasts won't spontaneously ignite!" her husband jokes, because that's exactly what you want to hear when adjusting to the news that you're a human baby-poison factory.) This sends her down a rabbit hole in search of deeper understanding of her own anatomy— into the evolutionary history of mammals, to Peru to investigate nursing and weaning, back to the first breast augmentation surgery, and all over the world to interview more boob experts than you can shake a pasty at.

And she discovers that breasts are complicated. Impossibly so. She learns that it’s the breast’s permeability that make it such an evolutionary powerhouse (lots and lots of estrogen receptors help human puberty occur at the optimal time; nutrient-rich breast milk makes for giant brains)—but that same permeability is also, partially, what causes one in eight women to develop breast cancer. Our breasts make us great but they also make us vulnerable, and you can’t help but come away from Williams’ book feeling a bit helpless. (Self-examinations! Self-examinations are key!) While she makes the story as dynamic as possible, there’s no escaping that this is science journalism—there are lots of PBDE levels and octa-203 and penta-47 and dioxin and “lobule type 4” and other such enemies of lively prose. But that’s OK—there are enough surprises and genuinely horrifying learning moments to keep a reader (especially a lady-reader), uh, latched on.

Five Things I Learned About Breasts From Florence Williams' Breasts

1. Women: Your boobs are trying to murder you.

Right now. All the time. The day you were born, your boobs took one look at you and were like, "Oh, no. No. Absolutely not. Hey, does anyone know where I can get some poison?" Turns out, everywhere! Breasts are largely made up of fatty tissue, and chemicals looooooooooove to accumulate in fatty tissue. Here’s a partial list from Williams: “paint thinners, dry-cleaning fluids, wood preservatives, toilet deodorizers, cosmetic additives, gasoline by-products, rocket fuel, termite poisons, fungicides, and flame-retardants." So what can you do to keep your chest-sponges safe from marauding chemicals? Nothing, pretty much, short of becoming a trillionaire and taking over literally every drug company and industry on earth. So get on it, concerned citizens! Step one: CoinStar.

2. Babies are cannibals and your breasts may be sexists.

A male baby requires almost 1,000 megajoules of energy in his first year of life. “That is the equivalent,” Williams writes, “of one thousand light trucks moving one hundred miles per hour.” And do you know where he gets all that energy? Not from the sun, unless you are a fern that somehow learned how to read the Internet (good job!). No, it’s from your boobs. HE’S EATING YOU. That little dude sucks it right out of you like the world’s chubbiest and least stealthy vampire. Which, of course, is exactly how it’s supposed to be—but it’s not surprising that so many women are leery of breast-feeding. On top of that, breasts (at least in rhesus macaque monkeys, whose milk is similar to humans) can actually determine whether a nursing baby is a boy or a girl, and adjust their milk production accordingly. Milk for girls is thin but abundant, while boy milk is fattier and scarcer—the theory being that girls then must stick closer to their mothers for frequent feedings, thus absorbing their social roles, while boys are easily sated and have time to play and explore. Um, way to prop up the patriarchy by reinforcing gender roles, monkey boobs.