FROM A WINDOW NEAR HER CELL, JEAN Harris can watch as the seagulls that circle the Bedford Hills Correctional Facility sail over the 12-foot fences topped with razor wire and swoop down among the prison's cinder-block and redbrick buildings. Watching the birds, she says, "leaves you suspecting that if you don't think you're a prisoner, then maybe you aren't one. The trick is just to keep looking up."

After 11 years in the maximum-security prison 40 miles north of Manhattan in New York's Westchester County, Harris has learned to treasure such artifice. Serving a 15-year-to-life sentence for the 1980 shooting death of Dr. Herman Tarnower, her longtime lover and the creator of the celebrated Scarsdale Diet, Harris, 68, is four years away from being eligible for parole and light-years from the life she once led as headmistress of the exclusive Madeira School for girls in McLean, Va. But Harris, who describes prison as a place where "good is bad and black is white and decency and truth are held laughable," has little use for bitterness. "You find very quickly in here that you've been one of the lucky ones," she says. "To sit around and nurse your wounds just makes you look like an idiot."

Instead, Harris, the mother of two grown sons, fills her days teaching parenting classes to the pregnant women and new mothers among her 690 fellow inmates. She spend-six hours a day caring for the infants in the prison nursery (inmates are allowed to keep infants under 12 months of age at the prison) and also helps Sister Elaine Roulet, founder of the prison's children's center, organize a summer visiting program in which local families host children of inmates. "You're lucky if you find a place where you can do some things that are useful." she says.

Her other outlet is writing. In her tenure at Bedford Hills, she has written three books, the latest of which, Marking Time, is a heart-wrenching collection of letters she wrote to author Shana Alexander. The two met when Alexander covered Harris's trial (her book Very Much a Lady detailed Harris's relationship with Tarnower) and became fast friends. "Jean's emotional strength is so powerful," says Alexander, who is currently teaching advanced nonfiction at the University of Southern California. "She didn't have that in the beginning. She just cried all the time."

Written between January 1989 and February 1991, the letters roughly chronicle Harris's life between New York Gov. Mario Cuomo's second and third refusals to grant her an early appearance before the parole board—a sore point with her supporters. While revealing Harris's bouts of frustration and despondency over her failing health (she has suffered two heart attacks during her time at Bedford Hills), the letters also paint a tragic portrait of her fellow inmates and their children. Says Harris: "I know a hundred women who make Job look like a crybaby."

Galvanized by what she has seen in prison—a woman who, along with her infant, is dying of AIDS; another who had the first of her 14 children when she was raped at the age of 10—Harris has become a crusader for the care and education of children. She has written Barbara Bush to encourage passage of national child care legislation (the First Lady wrote back offering her support), sent information on the Bedford Hills children's programs to other prisons around the country and studied everything she could about child development. "I hope that people will listen to some of the things I say about babies when I get out of here," she says. "It's illogical to be so careless about our children. It's coming back to haunt us."

As close as she is to the infants at Bedford Hills, Harris says that most of her fellow inmates remain strangers. "We've sort of gotten used to one another," she says. "Most of them have a lot of respect for their grandmothers, and I'm the closest thing to a grandmother around."

As for her own children (from her 19-year marriage to salesman Jim Harris, which ended in 1965), Jim, 38, owns a property management business on Long Island, and David, 41, a banker, lives in nearby Connecticut. Both visit their mother frequently.

Although she lives on an honor floor, "the cleanest and brightest housing" at Bedford Hills. Harris says that prison life can be grim. Up each morning at 5:30 for the first of the day's many head counts, Harris works in the nursery until 4 P.M., when she returns to her 6-foot by 10-foot cell to read "the mail, the paper, my magazines, anything I can get my hands on." She cannot answer all the thousands of letters she has received since she was put behind bars. Still, the letters have comforted her during her imprisonment. "There are an awful lot of women in this country who have had a lot of tragedy in their lives because of a man they loved," she says. Harris, who maintains that the shooting of Tarnower was an accident (she says she intended to kill herself, and the gun went off during a struggle), does not like to discuss him. "I'm sick of seeing book reviews that talk about the famous diet-doc murderess," she says. "I've grown far beyond that, and I deserve better."

Harris packs up all the letters she receives and ships them off to be stored at her alma mater, Smith College, in Northampton, Mass. "They don't have too many people convicted of murder who went to Smith," she laughs. "The library wanted them."

Almost every evening, Harris has dinner with two other honor-floor inmates in the unit's rec room. They prepare their meals in a small kitchen shared by 30 to 50 women. "I make the salads and wash the dishes, but they do most of the cooking," she says. "Until I started eating with these women, I had cereal and toast." Afterward she watches the MacNeil-Lehrer NewsHour, then has the guards lock her into her cell early to read until she falls asleep. "I get out of prison by reading," she explains.

Unsuccessful in their attempts to persuade Cuomo to allow Harris an early parole hearing, her lawyers are now petitioning the U.S. district court to overturn her conviction on grounds that her trial lawyer—Joel Aurnou—did not present the argument that Harris was severely emotionally disturbed at the time of the shooting. A hearing is expected next spring, but Harris isn't getting her hopes up. "I'd have to be an idiot to be optimistic," she says. "I've lost every appeal unanimously."

Sometimes, though, Harris does let herself dream about what life will be like when she is finally able to leave Bedford Hills. She has a cabin in New Hampshire where every fall friends plant crocuses and tulips in the hope that Harris will be home to enjoy them come spring. "I used to lie in bed and redecorate the living room and think about what I was going to do, but I've stopped doing that," she says. "Now I think I'll worry about that when I get up there. If I can just keep breathing long enough."