In the nineteen-fifties, the designers and developers of Detroit’s Lafayette Park believed that they had thought of everything to make city living as attractive as any suburb. A marquee architect from Chicago, Ludwig Mies van der Rohe, had created an array of housing options—rental and coöperative—in modernist slab towers, bars of attached town houses, and rows of low courtyard houses. The sharp-edged volumes were all bound together by landscaped greens and a large public park, romantically named the Plaisance, designed by Alfred Caldwell. The location was minutes from downtown. There was an adjacent shopping center. But, when the first “urban pioneers” began moving in, the ground had not yet been broken for the promised Chrysler Elementary School.

“This is a development designed to attract families,” Ruth Belew, a resident of the Pavilion apartments, told the Detroit Free Press. “If the children were forced to cross busy streets like Gratiot or Congress and Larned to get to existing schools, some parents would balk at moving in.” But until enough parents moved in, the school board wouldn’t release funds. The owners, to save their investments, had to think fast: they offered an unoccupied two-story town house to the Detroit Board of Education as a “one-room school,” and, on the recommendation of neighbors, hired Belew—a veteran of both the public-school system and the Red Cross service during the Second World War—to run it. Like a pioneer woman on the modernist frontier, Belew had to design what the architecture lacked: improvisation. With a summer to cram, she devised a course of study that would work for all sixteen pupils, using the city as classroom and calling on professional parents to fill in the curricular gaps. “I can’t sing, but we should be able to work something out,” she said.

Design and architecture have been, and remain, professions dominated by men. But when I set out to write my new book, “The Design of Childhood”—about the toys, playrooms, classrooms, and playgrounds that make up the worlds of children—I found a funny thing: women. Mostly women like Ruth Belew: handy, empathetic, often educators, ready to step in where they saw design with a capital “D” falling short. These women may not be listed as “inventors.” They may not have had the training to be “architects.” But they were the driving professional forces behind the beginnings of modern childhood and kindergarten education. Working with children, after all, was the rare field in which women’s gender was seen as an asset rather than an obstacle. As children gained their own spaces, their own toys, and their own diminutive furniture, beginning in the nineteenth century, refining, proselytizing, and testing designs meant for children was women’s work. We see their influence everywhere.

There’s the novelist Maria Edgeworth, who established the definition of a “good toy” that we still use today: simple shapes, natural materials, something that provides a spark to the imagination. In “Practical Education,” from 1798, Edgeworth and her father, Richard Lovell Edgeworth, describe the contents of the “rational toy-shop,” which would sell “balls, pulleys, wheels, strings, and strong little carts,” and also “pieces of wood of various shapes and sizes, which [children] may build up and pull down.” The idea was to offer sturdy playthings out of which children might make their own fun, rather than flimsy, colorful objects, made out of paper or tin, that came with a narrative embedded in their realistic form. “It is better that a child should tumble down or burn its fingers, than it should not learn the use of its limbs or its senses,” Edgeworth wrote, in an uncanny echo of the new child-rearing directive that risk can be educational.

There’s Caroline Pratt, who, in 1913, created the wooden unit blocks that continue to live on the open shelves of almost every kindergarten classroom, and developed a curriculum based on urban observation, coöperation, and hands-on building that is still in use at Manhattan’s City and Country School. It’s a man, Friedrich Froebel, the early-nineteenth-century German polymath, with his own sets of blocks, sticks, beans, and other building toys, who is credited with “inventing kindergarten,” but it was women, led by the reformer Elizabeth Peabody, who promoted and performed early-childhood education in late-nineteenth-century America. Froebel himself thought women were better at teaching small children—an early example of gender essentialism that was both helpful (more jobs for women) and hurtful (why only with children?).

Early kindergartens, which were incorporated into the displays at the 1876 World’s Fair, in Philadelphia, served primarily white and recently-arrived immigrant children. A separate set of women brought educational opportunity to African-American youth, often through the National Association of Colored Women’s Clubs. Elizabeth Jennings Graham—known as “the schoolteacher on the streetcar,” for her refusal, in 1854, to get off a lower Manhattan streetcar reserved for whites—went on to found the first kindergarten in New York for black children, in 1895, on the first floor of her house, at 237 West Forty-first Street. The Times wrote, “The children made art; they planted roots and seeds in the garden. ‘Love of the beautiful will be instilled into these youthful minds,’ read an article on the school.”

There’s Lady Allen of Hurtwood, who popularized “junk playgrounds” across Europe and the United States, in the nineteen-fifties and -sixties, arguing, in a time associated with the explosion of private consumer goods, that kids need risk and dirt and each other in order to learn. Lillian Ross covered one such playground, on East Seventieth Street in Manhattan, for The New Yorker, in July, 1971. Beverley Peyser, who ran the playground with a staff of fourteen teen-agers, explained to Ross, “This is a real adventure playground . . . . Here we’re doing things with earth, with water, with fire, with air . . . . Just the way kids in London during the Second World War used bombed-out sites to play in, to build exciting things with the rubble.”

This is not to say that men did not design for children: objects in miniature by famous architects include toys and furniture by Charles Eames (with his wife, Ray), schools and furniture by Eero Saarinen (and his first wife, Lily Swann), and playgrounds by Aldo van Eyck. (His boss at the Amsterdam Department of Urban Development was a woman, Jakoba Mulder.) But men had more options, and, when their work was shown, the children’s furniture and toys were often a footnote or sideline to some large adult enterprise. Women had to focus. Women had to share the spotlight, if they were in it at all.

My time spent writing about and researching the classroom and the playground has given me an expanded view of the history of design. Women have always been there—as recent histories have shown them to have been in computing, the sciences, and a host of other male-dominated fields—but we have overlooked their contributions. When it was recently announced that J. P. Morgan Chase would tear down 270 Park Avenue, a fifty-story skyscraper designed for Union Carbide by the firm Skidmore, Owings & Merrill, the preservationists’ defense included the note that the senior designer of the building was a woman, Natalie de Blois. To write a more inclusive version of architecture history required nothing more than adding one more name to the list of credits. But adding de Blois was no less than an admission that architecture is a collaborative art, and a skyscraper can never be the product of a single hand.

The architectural historian Gabrielle Esperdy says that getting de Blois’s name on the skyline might not even be the right goal. “If we want to talk about influence, talk about educators,” she told me of de Blois, who taught skyscraper design at the University of Texas at Austin for more than a decade. “Young men learning skyscraper design from this woman was powerful and transformative.” Women are now recognized as toy inventors (Debbie Sterling, with GoldieBlox) and have top billing as architects of children’s spaces (Jeanne Gang, of Studio Gang, with the Gilder Center at the American Museum of Natural History), which is great, but raising children, like architecture, also requires collaboration. Is it the man who invented building blocks who has the influence, or the hundreds of women that got them into children’s hands—and tinkered with their shapes and sizes along the way? The answer, of course, is both. Kindergarten lesson No. 1: sharing.