An excerpt from the introduction to Baby Meets World:

There is nothing less permanent in life than infancy: the point of being a baby is to stop being a baby. You get no bonus points for sticking around.

So writing about babies is a slippery experience: at some point your subjects just disappear. I began this book with a baby in my house. I ended it with a child who shows almost no sign of ever having been a baby. This is the fate of all babies: for millennia now, they have been vanishing.

You might think that these missing babies are a lot like the ones around us. After all, for many thousands of years, babies have been pretty predictable: they come out greasy and looking like Winston Churchill. (Even before Winston Churchill, they managed to look like Winston Churchill.) You might think that their stories—their experience of infancy—would be pretty predictable, too: they poop, they burp, they stagger around like early hominids. Who cares where all the babies have gone? Aren’t their stories mostly the same? Don’t they all smile and spit up? Don’t they all refuse to nap.

Their stories are not mostly the same. They are radically, outrageously, wondrously not the same.

This book tells the story of how some people used to think babies work. It also tells the story of how a lot of different people— some developmental psychologists, some physicians, some hunter-gatherers, some you and me—think they work now. I can inform you that among all these stories there is very, very little overlap. Only the species stays the same.

Infancy turns out to be far more varied and far less predictable than we often assume. It’s all deviations from the norm—even the developmental milestones themselves aren’t normal. Books about babies usually try to iron out all these wrinkles, to make infancy seem smooth, coherent, known. They leave out the dried cow’s teats and the skull molding.

But babies are gloriously unkempt. This book, like a newborn, is all wrinkles.

You will have noticed that the subtitle of this book begins with Suck. I should really explain.

A book about babies is supposed to begin with how. Most books in the parenting section are instruction manuals: they tell you how to get your child to sleep and how to get her into the accredited institution of your choice.

This book doesn’t begin with how for a very simple reason: it doesn’t tell you how to do anything. It solves no problems that have to be solved this instant: if your child is screaming right now, I cannot help you. Try the next book over.

What this book does do is step back from the problems, so they appear in perspective—perspective being that rarest commodity in parenting. Taking care of an infant is myopic madness: it is hard to make out much past the crib bumper. Your adult life shrinks until it resembles infancy itself: there is nothing remaining but essential bodily processes. I remember whole days from early parenthood when I thought about nothing but green poop. You’d never know there was more to think about infancy. Only by stepping back can you glimpse its strangeness and splendor.

Our approach to infancy is highly parochial: we raise and interpret our children in the hothouse of our present neuroses. We hyperventilate about a handful of things: co-sleeping versus letting them cry it out, slings versus strollers, even spoon-feeding versus finger-feeding. This book tries to break the hothouse glass. It looks forward to how scientists—doctors, developmental psychologists, neuroscientists—are shaping our understanding of how babies work. Theirs is the peer-reviewed baby of tomorrow, and we  expert-dependent Western parents will automatically adopt their baby as the new standard model. That’s the trade we parents first made almost a century ago: folk knowledge for scientific knowledge.

But not everyone made that trade. In much of the world, babies are understood in ways that seem surpassingly strange to us. This says more about us than them: from our scientific perspective, any model of infancy that isn’t at least pseudoscientific looks strange. It’s easy to assume that the history of infancy is a story of convergence, with everyone eventually arriving at the same conclusions. It isn’t. Like evolution on isolated islands, child-rearing practices are adaptations to specific conditions, which is why people can look at the same greasy newborn and come to so many different conclusions. John Locke insisted on leaky shoes and ice baths. The Beng of West Africa insist on enemas. This book is a mirror held up to a mirror: it looks at all these ways of looking.

It also glances backward to the babies of the past: how people in radically different  places and eras—the experts and the parents—once thought babies worked. Not just thought, were convinced. And people have believed—and still believe—that babies work in ways even weirder and more outlandish than you might expect: they once thought that colostrum was toxic and that touching a baby could be gravely dangerous. The peer-reviewed baby of tomorrow is just a version among the many that have proliferated over the years and across the globe. And for each society, its version of the baby was the baby—the only baby imaginable.

Once you see how many different babies there are and have been, and how many different ways people have insisted were the only ways of treating them, all child-rearing advice—a book of hows—begins to seem a little suspect. The grown-ups in the room have rarely agreed on how babies work, or even on what they need. Most of the hows about babies turn out to have actually been about the adults. You can’t write a brief history of babies without also writing a lengthy history of grown-ups.

So this isn’t a book about how to do things with babies. It’s a book about how babies do things. The subtitle begins with Suck for a somewhat improbable reason: this book is actually about sucking. Every new skill in infancy is all-consuming: a newborn will do nothing but suck; a newly smiling baby is as gregarious as a puppy; a baby who can grab something will grab everything; a baby who has just learned how to move will be a blur. But outside of developmental posters and nursing guides, no one says much about these activities: to everyone but the baby, the most visible parts of infancy are the most overlooked.

They shouldn’t  be. The activities herein—sucking, smiling, touching, toddling—cover a lot of what transpires during infancy: how a baby feeds and consoles herself; how she develops emotionally and socially; how she begins participating in her world; and how she learns to explore it. These are the big puzzle pieces you need to assemble an infant. (It’s an incomplete puzzle, of course: the baby in these pages does not cry or sleep. There’s so much happening in infancy—the amount of development is so dense— that if you covered everything you’d never get to anything.)

This book is also the backstory of a very specific baby, the raison d’être of the whole thing. He started it. I should really introduce him.

His story begins the instant I broke my elbow biking, a little less than a decade ago. Each of us arrives in this world to a history that precedes us. His was written on the unyielding asphalt in front of a White Castle franchise.

I had to wear a sling on my right arm for the next few months, and at a Fourth of July party, I had to scrape the burnt bits off my hot dog bun with my non-burnt bit-scraping arm and someone standing nearby was audibly impressed at my wrong-armed coordination. It is the only recorded episode of coordination in my life but never mind. We spent the rest of the night on the rooftop talking. She was dating someone else but never mind. It was Independence Day. There were fireworks.  It was Independence Day in Chicago, so the fireworks were interrupted by occasional celebratory gunshots, but still: fireworks.

Isaiah was born some four years later. The elbow’s doing fine.