The success of "The Girls from Ames," the best-selling book about the 40-year friendship of a group of women originally from Iowa, has prompted a spate of national news stories about the importance of friendship to emotional and physical well-being. One study shows that if you have lots of friends you're likely to live longer, while another concludes that friends help slow memory loss (boy, do we hope that's true!).

Another, not-so-healthy friendship finding: If your friends gain weight, you probably will, too. For good or for ill, all the studies say, friends make a big difference in our lives, maybe even more than family.

We've been thinking a lot about friendship lately. Cokie recently joined her Wellesley classmates for their 45th college reunion. There, she reunited with a group of women who have always stayed in touch and have been getting together quasi-regularly for the past 20 years or so.

Unfortunately, a sad occasion quickly overshadowed that happy one the memorial service for another college friend of ours, Eden Ross Lipson. Hundreds of people canceled their summer-weekend plans last Saturday to honor Eden's life.

The published and broadcast obituaries after she died in mid-May chronicled her achievements as an editor, author and expert in the field of children's books. And while speakers at her service talked about those aspects of her life, acknowledging the kinds of accomplishments that show up in the newspaper and on the air, Eden's eulogists underlined another, and to her, far more important part of her life: her remarkable talent for friendship.

At the Wellesley reunion, as with the "girls" from Ames (who do seem like girls to the 1964 contingent, since they are only slightly older than some of our children), the women in our class shared a period of time we were all roughly the same age when outside events helped shape us. Our college years coincided with the Kennedy presidency: Elected in the fall of our freshman year, JFK died in the fall of our senior year.

We shared that space in history with Eden as well; we met through student politics and the three of us graduated in the same year from different schools, but her friendships spanned the decades, from our parents' generation to our grandchildren's. She understood that she had something to learn from and teach people of all ages. Her friends' kids became her friends, and her friends' kids' kids became her delight.

At The New York Times, where she was an editor for more than 31 years, Eden was known as "the mother of mentors and the mentor of mothers." Because of her love for babies, she would scoop up new mothers, quell their fears, and embrace their joys. That celebration of children, especially her own Margo and Garth, was the secret to her success as a critic and promoter of children's books. She considered children an integral part of her great circle of friends.

Asked by the NPR program "Talk of the Nation" to contribute to a "library of democracy" one Election Day, Eden advised listeners to think about "where democracy begins and isn't it on the playground and in the school yard?" By reminding us that those little people are working out government by consent, Eden showed us how seriously she took children. She also took seriously that other often-disenfranchised group the very old.

It's ironic that someone with such a capacity for friendship should not enjoy the long life the studies say these relationships can promote. But she did live longer with a pancreatic-cancer diagnosis than most people do, and the teams of doctors and nurses who cared for her quickly learned that she was more interested in them as people than in what they could do for her. They, too, had become her friends. Even in an emergency, as she was wheeled into the hospital, Eden would see a familiar nurse and ask after her children by name.

We Eden Lipson's friends inherit each other. She deliberately widened all of our own friendship circles, constantly connecting us to each other and to each other's children, and our children to each other as well. We don't know whether our lives will be longer because of those friendships; we do know they have been and will be richer, as have our children's lives. And who knows, perhaps their children will connect as well. So the longevity that Eden's friendship provided was of a different sort. Typically, it benefits us, not her.

Cokie Roberts' latest book is "Ladies of Liberty: The Women Who Shaped Our Nation" (William Morrow, 2008). Steve and Cokie Roberts can be reached at stevecokie@gmail.com.