MARIA CONCEPCION walked carefully, keeping to the middle of the white dusty road, where the maguey thorns and the treacherous curved spines of organ cactus had not gathered so profusely." So Katherine Ann Porter, who died on Thursday at age 90 in a Silver Spring nursing home, began the first of the stories that established her in the 1930s and '40s as an eminent American craftsman or short stories and novellas. Maria Concepcion, like almost all of Miss Porter's heroines -- no matter in what exotic or familiar milieu she placed them -- was essentially Miss Porter. She was one who walked carefully, aware -- sometimes to the point of being overwhelmed -- of the perils of the road.

From her native South Miss Porter took a sense of a culture in shock and from a succession of illnesses a perception of life as seen by one with a fevered and tenuous hold on it. The larger 20th century world she entered was one "heaving in the sickness of a millenial change." Her purpose in writing was to hold a few individuals up to these various flames and to try to salvage for them a residue of peace and serenity, or at least to have them survive. This was what was left to Maranda in "Pale Horse, Pale Rider," Miss Porter's best-known story. Not even that was left to the passengers of the "Ship of Fools," her one long novel, published in 1962 to great commerical if not critical success. Survival in dignity was for her a moral act, perhaps the only one.

And, of course, she wrote exquisitely, with an economy and precision of expression and a constantly startling lushness of imagination, as though her thoughts and words had been stored up for years. In fact, this was how she worked. Her ideas could take decades to germinate. Then she, wrote them down quickly, finishing stories in days and barely revising. Read this, from "The Jilting of Granny Weatherall": "Granny lay curled down within herself, amazed and watchful, staring at the point of light that was herself, her body was now only a deeper mass of shadow in an endless darkness and this darkness would curl around the light and swallow it up. . . . She stretched herself with a deep breath and blew out the light."