Peggy Talman knew better than anyone that she should not smoke.

In July 1968, her husband, 53-year-old William Talman, taped a landmark antismoking public service announcement that warned of the hazards of cigarettes. Talman, the actor who played the perpetually unsuccessful district attorney, Hamilton Burger, on the fabled ''Perry Mason'' show from 1957 to 1966, was dying of lung cancer.

Yet, even after she watched smoking kill her husband, even after she took up his antismoking crusade, her hands somehow felt empty without a cigarette. Within a few years, Peggy Talman was smoking again and, last August, she got the grim news: Just like her husband, she had lung cancer.

''It's just awful,'' Talman said she thought at the time. ''It disgusts me totally.''

Unfortunately, as organizers of the Great American Smokeout celebrate the antismoking event's 25th anniversary this week, Peggy Talman's story is increasingly typical. Of the 49 million current American smokers, about 80 percent have tried to quit and failed at least once, giving former cigarette smokers a relapse rate nearly equal to former heroin addicts. And none of the stop-smoking programs - from nicotine gum to acupuncture - are likely to work unless the smoker is both motivated and prepared for withdrawal pains.

''Most of the people who were lighter smokers or not as heavily addicted, they quit, a lot of them quit in the early `80s and `90s,'' said Dr. Doug Jorenby, director of clinical services at the Center for Tobacco Research and Intervention at the University of Wisconsin. ''Now, what you're seeing, unfortunately, are people who, when they are confronted with incontrovertible evidence [of smoking's dangers], they still keep smoking.''

Despite billions spent in the war on smoking, researchers still know relatively little about what lures former smokers back, largely because tobacco dependence is a hard-to-measure mixture of nicotine craving and psychological need. The Talmans - including several children who also took up smoking - offer a case study in just how habit and family history can trump both common sense and tragedy. Peggy Talman said she hopes that her story, one of the sadder ironies in the history of the antismoking movement, can educate the public about a problem that just won't go away.

William Talman was already an accomplished movie actor in 1957 when he landed the role of Hamilton Burger, the prosecutor who was always being outwitted by defense attorney Perry Mason, played by Raymond Burr. Yet, despite his great achievements in Hollywood, Talman experienced his share of adversity. By the late 1950s, when Talman met Peggy Flanigan at a mutual friend's poker party, he had two failed marriages behind him and a history of heavy drinking.

But it was another behavior common to actors that would ultimately doom Bill Talman. Long after he had married Flanigan in 1958 and gotten his life in order, Talman continued to smoke cigarettes, a habit he had begun at age 12. Indeed, despite growing warnings about the dangers of smoking, Talman smoked as many as three packs per day.

In September 1967, Talman underwent a chest X-ray for a persistent cough. The results were ominous - an apparent cancer in his left lung. A biopsy obtained during surgery provided even worse news. The cancer's advanced stage made it inoperable.

Despite radiotherapy treatments, the cancer within months had spread to the actor's other lung and his brain. As the summer of 1968 progressed, Talman required increasing doses of morphine, which relieved the pain but made him groggy. Hardest of all was breaking the bad news to the six Talman children, four from previous marriages and two, Tim and Susan, from Bill and Peggy's marriage.

Then, in July 1968, Bill Talman made a remarkable decision: He phoned the American Cancer Society. Eventually, the call was routed to Irving Rimer, head of publicity for the organization. ''I want to do a TV spot,'' the actor said. ''I know exactly what I want to say.'' A dying man telling the story of how he began smoking, Talman believed, could prevent others from ever starting.

Rimer was overwhelmed. ''The American Cancer Society was never pleased about putting out spots of people dying,'' he recalled. ''But this one had to be done.'' In the late 1960s, antismoking public service announcements had just begun to appear on television, but there had never been anything like the spot that Talman was about to film.

The taping, at Talman's home in Encino, Calif., was not easy. He could barely perform, given both his constant pain and morphine-induced haze. Peggy Talman recalled frequent breaks. The cameramen and others in attendance, including Burr, waited patiently.

The spot opened with pictures of Talman's carefree children playing in the yard. Then the cameras moved inside, where the actor sat on a chair. ''My name is Bill Talman,'' he began, calling himself ''the most unsuccessful prosecuting attorney in the history of the legal profession.''

''I want to tell you about an early case,'' he stated. ''When I was a kid, 8 or 9, my Dad offered me $1,000 and a gold watch if I would get to the age of 21 without smoking a cigarette. I lost that case before I was 12.'' Of all his cases, Talman explained, this was the one he most regretted losing.

''I have lung cancer,'' Talman stated, ''which means that my time with this family that I love so much is shorter, and that makes the price of losing that bet more than I could afford, more than most of you can afford, more than almost anyone in the world can readily afford.''

Gaunt and in obvious pain, Talman concluded, ''Let me join you in spirit, in prayer, even if I'm gone when you see me speak these words to you.'' By Aug. 30, 1968, some six weeks later, he was dead. The message was first broadcast the next month.

Talman's message won praise among viewers, many of whom vividly remembered it for decades and credited it for getting them to quit smoking. Once Talman broke the ice, numerous Hollywood stars, including Tony Curtis and Sammy Davis Jr., openly criticized cigarettes. In later years, other dying celebrities, such as Yul Brynner, would tape similar warnings.

But the most intense reaction came from the Talman family. Given William Talman's reference to his own father during the announcement, the message was especially intense for youngest son, Tim. ''I remember this sticking with me for so long,'' Tim Talman, now 36, recalled. When Tim was in the eighth grade, he made a model of cancerous human lungs for a biology project. During his presentation, he showed the public-service spot. ''Here's my father giving his message to my classmates,'' he thought. When the lights went up, his teacher and several students were in tears.

William Talman's public death was hard on his son. ''As a child, I was riddled with nightmares,'' Tim Talman recalled. Still, Tim knew almost immediately that he would follow his father's footsteps and become an actor. He has succeeded in this task, having extensively toured in shows such as ''Cats'' and ''Peter Pan.'' ''My father is my hero,'' Talman said. ''It's not surprising that he went to such lengths to make an antismoking spot.''

But, as an adolescent, Tim Talman found himself repeating his father's mistakes. ''I started to smoke in high school, then continued in college,'' he said. Alcoholism, which eventually induced Tim to join Alcoholics Anonymous, fostered his smoking habit. ''Not a cigarette went by,'' he said, ''that I didn't think of my Dad, that I didn't feel remorse, that I didn't feel guilt.'' He even recalls blowing smoke in the opposite direction from his father's pictures, which graced his apartments walls, as if that would somehow prevent William Talman from learning of his son's misdeeds. ''My Dad's message was: `Don't be a loser. Don't smoke.' But I was a loser.''

Peggy Talman had an even harder time. By fall 1968, television stations across the country were showing her late husband's antismoking announcement. One night, the message was broadcast while Peggy Talman was watching television. She had a cigarette in her hand. ''Daddy wants you to stop smoking,'' 4-year-old Tim said as he sat next to her. Peggy Talman quit cigarettes the next day.

During 1969 and 1970, Talman served as a spokeswoman for the American Cancer Society, traveling the country with her antismoking message. Perhaps because she was not accustomed to public speaking, her performances were especially moving and genuine. But, by 1971, Talman, eager to spend time with her children, returned home.

Unfortunately, she also resumed smoking. Like William Talman, Peggy had first tried cigarettes in her teens. ''My mother smoked, and my aunts and uncles smoked,'' she said. ''Nobody thought much of it in those days.''

In recalling why she resumed smoking in the early 1970s, Talman said she believes that she was psychologically addicted. Cigarettes, she said, were both enjoyable and comfortable. ''When I quit, it was the habit I missed the most. I didn't know what to do with my hands.''

As more and more information emerged about the dangers of cigarette smoking, the Talman children beseeched their mother to quit again. But most of them, aside from youngest daughter Susan, eventually themselves smoked. Ultimately, it was easier to do what Bill Talman did - not what he said.

As the years passed, Peggy Talman was able to cut back from more than two packs daily to less than one pack. She wanted to quit entirely but never did.

''I thought it was kind of silly to keep smoking,'' she said, ''but I kept on.''

Smokers now can choose from a series of products - ranging from antidepressant medications to nicotine gum, patches and nasal spray - that can double the chances of quitting. But given the high rates of relapse, smokers may need several attempts before they quit for good. Unfortunately, noted Columbia University psychologist and researcher Dan Seidman, there are no special services for really addicted smokers.

Seidman stated that doctors must treat smoking as a ''chronic relapsing disorder'' and a ''lifelong disability'' that requires repeated interventions and assistance.

Health professionals, however, are notoriously lax in bringing up the subject of cigarettes: Only half of smokers have ever been told to quit by their physicians. Over the years, Peggy Talman said, her doctors only raised the issue periodically. When one physician offered her nicotine patches, she could not afford them.

Today, Peggy Talman's lung cancer is advanced and inoperable. Indeed, the difficulty in discovering lung cancer in its early stages helps make it the deadliest cancer, killing more than 150,000 Americans each year. Talman, who now lives in the Portland, Ore., area, is undergoing chemotherapy. At the age of 74, she continues to work at the local Costco, preparing food samples for the customers. More than 100 of Talman's coworkers, after learning of her illness, organized a party in her honor.

Although others might have responded to a diagnosis of lung cancer with guilt and remorse, Talman refuses to do so. ''I'm not going to beat myself up that way,'' she said. ''There are no what-if's.'' Nor does she blame the cigarette industry, which concealed the nature of nicotine addiction when she began smoking and currently spends more than $8 billion annually to market its product - often using manipulative techniques.

''I made my own choices,'' Talman conceded. ''They may not have been good ones, but they were mine.''

Tim Talman, meanwhile, is struggling to deal with his mother's news. Noting how Peggy successfully raised six children as a single parent, he calls her his other hero. ''It would be easy to blame my mother, but I won't.'' Tobacco, he stressed, is an addiction, not a human failing.

Tim Talman often visits his father's grave at Forest Lawn Cemetery in Los Angeles, where his mother eventually will be buried. When she dies, he said, ''it will really be about smoking. Tobacco is going to have another couple of notches on its belt.''

Talman himself continues to struggle with his family's demon. He has not smoked a cigarette in almost a year, and vows never to take a puff again. After all, he owes it to his Dad - and to his Mom.

This story ran in the Boston Globe on 11/13/2001.