I first met Nancy Reagan's mother, Edie Davis, in the early 1940s in Chicago. I was in radio and so was she, as an actress. We became great pals, this extraordinarily high-spirited, funny and -- yes -- earthy woman and I, and we remained so over the years. She died this week at the age of 91. So utterly different from her daughter in many ways and yet so close to her, Edie Davis is a part of the Reagan story that has never been widely understood.

When I met her, she was acting in the radio soap operas. Chicago was the capital of the soaps then, and she never wanted for work. She played the society grande dame on "Betty & Bob," and she also played the black maid Mattie on the same show. She was a regular on "Stepmother."

We would spend raucous mornings in the green room at WBBM, where actors and announcers and news folk milled about over gossip and coffee. It seemed that every day Edie had another sunny obscene greeting and another dirty joke to tell. We loved her. And we wondered about the grave and lovely daughter she had spawned, young Nancy in her white gloves and Peter Pan collars and patent leather pumps. It was obvious she was fascinated by her mother, caught up in her humor and energy and impulsiveness, and wistful that she didn't have more of that herself.

Nancy had been the flower girl at her mother's second wedding. That was in 1929 in Chicago, where Edie had gone to resume acting after a failed marriage to a handsome young auto salesman. She had first gone on the stage in a Washington theater managed by her brother Joe. He needed a youngster to die on stage -- no lines, just die. Edith did it superbly. And then to reassure the audience that she was not genuinely dead, she rose and waved, to wild applause. She lost that job, but she knew this was the life for her.

She was in Chicago playing in the touring company of "Elmer the Great" with Walter Huston and Kay Francis when she met a rising young neurosurgeon named Loyal Davis. He was stiff, formal, a stickler; she was warm, outgoing, wicked. He took her back off the stage. From 1929 on, Edie Davis set about making a happy, fulfilling and varied life for Loyal, his son Richard and Nancy. In her spare time she threw herself into good works, such as the Chicago Community Fund; she was chairman of its women's division for 25 years, and no figurehead but rather a hard and steady worker.

She couldn't stay away from acting, though, and that's why I came to know her at WBBM.

After their Chicago years, Edie and Loyal moved in retirement to Arizona. She worked there helping retarded children, and in 1983 she got the Arizona Lifetime Achievement Award from the Association for Retarded Citizens of Arizona.

When I first heard of Nancy Reagan's involvement with her Foster Grandparent Program, I knew whose example she was following. And when Nancy set about fighting drug abuse among young people, amid the snickering of those Washington skeptics who said it was just a public relations device to blur the image of the first lady as a brittle Beverly Hills matron, I knew that it was Edie's daughter Nancy doing what her mother had first taught her: that responsibility goes with privilege.

Which brings us foursquare to the first lady, whose recent weeks have been so rending. Her father, upon whom she depended so, whom she loved and admired greatly, died five years ago. Her mother had been ailing, confined to a wheelchair and dispirited the past few years. The troubles of the administration and then her own breast cancer operation -- all this would be enough to do in a Valkyrie. Nancy survived and smiled, though, and cheerled and went about her appointed rounds. Then came Edie Davis' death, and somehow it seemed to take Nancy Reagan's breath away.

I can understand why.

The writer is a correspondent for CBS News.