It was the summer of 1945, and 15 women sat in Hazel Mahler's North Arlington living room trying to figure out what to do with their children.

"I had a son who was 4 years old," Mahler recalled. "There were no kindergartens at that time in Arlington. He had had so much adult attention but very few playmates, and we couldn't afford an expensive private school."

The other women, most of them first-time mothers, had small children and similar concerns. Finally, hours of brainstorming yielded the idea of a cooperative preschool; parents would write the school's constitution, pay its teacher, paint its floors and participate in its classes. A little more discussion produced a name for the school: Overlee, after the nearby Overlee Knolls neighborhood.

The parents were ambitious but pragmatic. "We thought it was just a [postwar] thing," said Mahler.

"We thought we'd have it for a few years, then take our kids out and it would die," said Nellie Grant, another founder.

Forty years later, founders Mahler, Grant and Elizabeth Marston came back Saturday to mark the anniversary of the school they thought would never last -- along with 130 other parents and children who came to celebrate an enduring cooperative.

In the rooms of St. Mark's United Methodist Church on North Glebe Road there were signs of the timelessness of children. On the bulletin boards were faded newspaper clippings and photographs whose dates didn't really matter: children in Easter bonnets, children at the Capitol, children cradling baby chicks.

There was crepe paper on the ceiling, birthday cake on the table, toddlers playing on the floor and -- from the adults -- emphatic praise for a school they said teaches parents as much as it teaches their children.

Because each parent participates as a teacher's aide once every two or three weeks, "You watch other parents handle temper tantrums and crises -- it's a wonderful education in parenting," said Joan Anthony, whose son Peter, 3, attends Overlee.

Overlee Preschool Association Inc. enrolls 38 children. The 2-year-old Yellow Birds attend two or three afternoons a week, while the 3- and 4-year-olds (Bluebirds and Redbirds) go to school for three hours every morning.

Unlike some nursery schools that stress reading readiness, Overlee's two teachers try to encourage social and emotional development rather than specific skills to prepare for kindergarten.

There is a hour of free play in the mornings at Overlee, then snacks and nap time, singing and stories, art projects and field trips.

"Our feeling at Overlee is that children are pushed into that sort of thing [reading readiness] far too early these days," said Anthony. "We're really keen for the social and emotional development."

Marston, Mahler and Grant, reunited for the first time in years, fueled each other's memories of Overlee's early years.

"We were all tied down with the children," said Mahler. "It was an outlet for the mothers. I had been an only child. I had never been around a baby in my life until I had Bill. I was scared to death."

"I had no idea what to do or how to handle children," said Grant.

"I didn't either!" said Marston.

The school began in a burst of postwar energy. One of its first newsletters, from February 1946, read, "The world of today and of the future is radically different from what it was before the war. Every place is nearer and everything is faster . . . . We haven't time to lose.

"We must think . . . am I, as a parent, satisfied with this world into which I have brought my child, or are there things I must do to help improve it?"

Overlee was a radical idea for its time. "There was a definite school of thought that said, these kids should not be in school at that age; they should be home with their mothers," recalled Thomas Mills, the husband of another founding member.

The founders were undaunted. Marston and her husband, a woodworker, sawed and sanded dozens of wooden blocks. They invited child psychologists to speak at the parents' monthly meetings. They hunted for books about early childhood development. One early newsletter even noted some equal-opportunity participation in Overlee: "Our school floors are now a lovely green, thanks to the efforts of the fathers."

"I thought we were kind of far out," said Marston.

The school, begun with 15 families in Resurrection Lutheran Church on Washington Boulevard, flourished. "We were very lucky," Mahler said. "It did the mothers equally as much good, if not more, than it did the children."

Forty years later, some things have changed at Overlee. Tuition, $12 a month when the school began, is now $68 a month. The dress code requiring mothers to wear skirts or dresses when they helped out in school was abolished in the late 1960s, and more fathers now show up to take their turn at being the teacher's aide.

Fred Hufford, whose daughter Ellen attends Overlee, played his clarinet for her class. "It's the only group I'd ever do that for," he said. "I think it's helpful for the kids to see the other kids' parents -- they learn how other kids relate to their parents."

As more two-career families join the school, it is struggling with new issues of continuity and survival. "The questions now are, 'Will we allow a baby sitter or a nanny to co-op instead of Mom or Dad?' " said Susan Marks, who has sent two children to Overlee. "What we're struggling with is different ways to keep the co-op idea alive while adapting to the times."

Despite the changes, the comments of some parents echo unchanged over the decades. "As a new mother, it [motherhood] is so intimidating," said Diane Goldberg. "You think your child is an idiot or a lunatic."

"Especially when you're just at home with your child," said Cathy Denk, "you think, 'Gee, is everybody's child doing this?' It's usually very comforting to find out that your child is normal."