Steamy afternoons of summer, a heat wave on the mainland, and we are three generations looking out at the sea as smooth as glass, gazing at another small spruce-covered island across the water. No breeze to flutter the daisies in the field or push the becalmed sailboat from view. Even the bugs are quiet.

Then the baby howls.

I pick up my grandson and hug him. His mother--my daughter--starts to wake from her nap but I want her to sleep; she and her husband haven't had a good night's sleep in months and this is vacation. So I cuddle this 5-month-old dynamo and rock and hum until the storm passes. Must be those two bottom teeth coming in, or a sudden nightmare. With all the rocking and humming, his body goes soft and limp against my chest. I kiss the new-grown fuzz on his head. It is quiet again, the sun a little lower in the sky.

This is the moment when, like Faust, you want to say stop. Stop the planet spinning. Stop because this is a moment of such joy. To be a grandparent, to hold the baby of your baby! To know that generation after generation, parents and children and their children will watch the same sinking sun behind the same islands of spruce--perhaps this is a glimpse of eternity.

With all the how-to advice books for every stage of life from potty training to retirement, the role of grandparenting still doesn't get the attention it deserves. Grandparents belong to the steward generation that is invested emotionally and financially in the very young. There can be something magic in relationships that jump the in-between generation of parents, making it easier for both ends of the age spectrum to connect.

For the most part, the only time that this steward generation is put in the spotlight is when there is a crisis with the parents and the older ones take over the custodial role for the young children.

Sometimes this makes for sweet drama. The new movie "Tea With Mussolini" is about an Italian boy during World War II who is essentially adopted by a gang of eccentric British ladies caught in Italy by the war. He was born out of wedlock; his mother is dead, his father preoccupied with a wife and other diversions. But the boy attaches to this older, art-loving group, which also includes a young, flamboyant American friend of his mother's. None of the women is his biological grandmother, but they play the stewardship role.

Today in the United States, grandparents' taking care of their children's children has become commonplace. Nearly 5.5 million children live with grandparents, according to a July report from the Census Bureau. The number has grown steadily since 1970, when 2.2 million children lived with grandparents.

But this is not always a sweet story. Most families raised by grandparents, and especially those raised by grandmothers, face tremendous economic and social hardships. More than a quarter of the grandchildren are poor, and one-third have no health insurance. "We find that many grandparents and the grandchildren they are raising or are helping to raise are in dire economic straits," conclude researchers Lynne M. Casper and Kenneth R. Bryson in their report.

Often grandparents take over in the face of tragedy: the death, illness, disability or disappearance of one parent or both. The family is already stressed and hurting. Where would these children be without a grandparent to look after them?

Grandparents who are raising children deserve special praise and support. They have taken on tremendous responsibility. According to the Census Bureau report, they are relatively young. Some 85 percent of grandmothers and nearly 80 percent of grandfathers are under age 65. The majority are working. Half of their grandchildren are under age 6.

I think of my own grandparents--my two grandmothers especially. And my great-aunt Gladys. They all helped raised me. I spent so much time with them partly because my mother was disabled by the demons of addiction and mental illness. If the Census Bureau researchers had visited our household back then, they probably would have labeled us a family in crisis.

But when I was with my Gran or Granny or Aunt Gladys, we didn't dwell on that. We created a secure world of stories and laughter and music and love. They were all generous with their time and affection--and they made sure I had the right clothes as well as the right manners.

They lived long--two of them reached the age of 98--but I lost these strong women when I was in my thirties, as I was raising my own children. I wondered how they had done it--young children can be so draining. These grandmothers spent so much time and did so much for all their grandchildren. I am indebted to them and have worried over the years that I didn't thank them enough.

Now I know why they did it.

My grandson wakes up in my arms and grabs my little finger. He gives me a drooling smile. I sing to him, say his name, tickle him, and we both chortle long and loud. A little breeze has picked up and there are ripples on the water.

My daughter gets up to feed him. She sees us playing together and jokes: "You can hold him, Mom, but you can't kidnap him!" We both laugh and I hand him to her.

I am lucky. My daughter and her husband are strong, healthy parents. But I'm in the wings--in the best of times and other times, too. That's what it means to belong to the steward generation.