It's a cold morning in February when social worker David Kaczynski arrives at the home of a 15-year-old boy -- one of his "clients." The boy, his grandmother and uncle climb into Kaczynski's tan Chevrolet Prizm. He's taking them to a graduation ceremony of sorts. The boy's mother has successfully completed her time in a drug rehabilitation program, and is coming home, so everyone is in a festive mood.

As the group heads west on Interstate 90 in Upstate New York, they chat about the grandmother's church work, and about the mother's crack addiction and her decision seven months before to finally try and kick it. After a while the conversation slows. The passengers doze a little. Cars and huge trucks blaze by. Finally the uncle begins edging around the subject that everyone edges around with David Kaczynski.

When you're a black man in America, he begins, it's easy to feel victimized. To get really angry at society. So angry, in fact, that there have been times when he has wanted to hurt someone. Wanted to get some sort of revenge. He understands that impulse.

The uncle is looking at Kaczynski in the rearview mirror. He's waiting for a response. Kaczynski, a tall 51-year-old man with salt-and-pepper hair and a gentle demeanor, has been listening quietly. He knows exactly where the uncle is heading with his careful words. But before he can say anything, another voice pipes in. It's the 15-year-old in the back seat. And he gets to the real issue at hand. "Dave?" the boy asks the brother of the anti-technology terrorist known as the Unabomber. "Why'd you turn him in?"

So why did he do it? Why does a brother betray a brother? Violate memories of childhood camping trips, board games at the kitchen table and even the deeply personal alienation that came later, to tell the FBI: I think my older brother is a murderer, the mentally ill bomber you have been searching for, take him.

And how do you live with the consequences of this one act: with the FBI hunting down your brother in Montana and parading him, handcuffed, before the world as a vicious psychopath? With the prosecutors seeking to put him to death? With Ted, who craved wilderness and isolation, locked up and regimented for life in a tiny prison cell?

For almost 18 years, Theodore Kaczynski managed to escape detection, and mail his bombs to those he deemed responsible for the technology age -- computer store owners, engineering professors, businessmen. Until David, along with his wife, Linda Patrik, eventually read the Unabomber's rambling 35,000-word manifesto and felt a chill. He noticed an eerie similarity to language in his brother's angry and rambling letters home. And decided he had to do something.

How do you live with the consequences?

David goes to work every day, listens to country music, participates in a poetry group, plays baseball in a summer league and takes vacations with his wife at their Texas cabin -- and never quite forgets that his older brother sits in a Florence, Colo., federal maximum security prison, doing who knows what. Thinking who knows what. Ted hasn't communicated with him, or anyone in the family, since the FBI agents appeared at his remote Montana shack, told him, "Ted, we need to talk," and dragged him off to prison.

It's evening and David's flat Midwestern voice is low after hours of talking about Ted and his arrest and the last six years. His Schenectady, N.Y., house is dim now, the only illumination from an occasional car going by.

His is a tale of two brothers in conflict, not like Cain and Abel, whose relationship was overtaken by envy, anger and eventually murder. But two brothers whose relationship grew and then splintered in a more modern story of psychiatrists, mental illness, philosophical bents and mail bombs.

They were two brothers so close, as they grew up in the Chicago suburb of Evergreen Park, Ill., that their mother recalls their relationship as "beautiful." Wanda Kaczynski, a widow now, lives alone in a sparsely decorated apartment in Scotia, not far from David's house. In the front hall on a table are a few photographs of her two sons. Wanda, a small, roundish woman with short gray hair, has spent many hours -- years, really -- puzzling over what went wrong with her older son. But she knows for sure that Ted had a powerful devotion to David.

Ted was 71/2 years old when David was born and already a loner, uncomfortable with kids his own age. Wanda recalls bringing the new baby home from the hospital: "I put David in Ted's arms and said, 'You know, we three, you, your daddy and I, have to take care of him so that he'll grow up to be as big and nice as you are.' And he was hooked from that time on."

David was often the only human Ted seemed to care about, Wanda says. And David looked up to him in turn, impressed by how smart and independent he seemed. Ted was hugely protective of his little brother. When Ted had nightmares they were sometimes about his inability to protect David. Once, Wanda remembers, Ted dreamed about starving children in poor countries (a topic in the news then) and saw his younger brother withering away with Ted unable to get to him to help. Later, he dreamed that he had to defend David from members of an evil cult.

The boys grew to be so different: Ted a moody loner, brilliant, intolerant, rigid; David more outgoing, compassionate, easy to be around. As they grew they differed in their beliefs, too. Ted tried to mentor David in the "correct" ways of thinking about things, taking issue with David's decision to remain a vegetarian, his aversion to guns, even arguing about the degree to which logic alone can reveal "the truth." David and his parents often felt they had to be very careful around Ted, or risk upsetting what seemed like a delicately balanced psyche.

Both Ted and David loved the wilderness, and one summer they traveled around British Columbia together, looking to buy a remote parcel of land. They found a place, but before they could buy it, Ted suddenly shut down, refusing to speak. He never explained, and David sensed he shouldn't push. In 1971, the two did buy some land together outside Lincoln, Mont., and Ted put up a primitive 10-by-12-foot shack, with no running water or electricity and homemade furniture, a cast-iron stove and just two small windows. He settled there that year, far from the nearest human, occasionally writing to the family.

In the mid-1970s, Ted sent a letter to his mother and father, unleashing a torrent of hostility and abuse for failing him as parents, and for his nearly paralyzing uneasiness with people. Wanda recalls that when David defended them in a letter to Ted, Ted threatened to cut off all contact with him as well. Their relationship recovered, eventually, but it remained prickly when certain subjects were raised.

In May 1978 the first bomb attributed to the Unabomber exploded at Northwestern University outside Chicago, injuring a security guard. As far as the Kaczynskis knew, Ted was in Montana, eking out a sparse existence. A few months later Ted returned home to the Chicago area, and began working at a foam rubber factory where his father, Ted Sr., was a manager and David also worked, at times as a fill-in supervisor. After a female co-worker refused to go out with Ted on a third date, he posted insulting limericks about her around the building. David, in what he now sees as a foreshadowing, was the one who fired him. Ted angrily locked himself in his room for days. Several months later he moved back to Montana, this time for good.

He eventually began forbidding family visits, and his letters home became less and less frequent and more angry. By 1990, 11 more bombs attributed to the Unabomber had detonated around the country, killing one person and injuring 20 others. Ted's communication with David and his parents had all but ceased. He begged David to stop his mother from writing to him. "Every time I get a letter from a family member, my heart pounds and I'm going to die," he wrote.

That year, David wrote Ted to say their father was terminally sick; Ted acknowledged receiving the letter, but nothing more. Later in the year, when he could no longer bear the pain of the lung cancer that had spread to his spine, Ted Sr. committed suicide. Ted Jr. did not return home for the memorial service -- though he spoke briefly by telephone with his mother but hung up abruptly when he got too emotional.

David and his wife, a philosophy professor who had never met Ted but read some of his letters, were worried about Ted's mental condition. And then on a trip to Paris in 1995, Linda read a newspaper article in the International Herald Tribune about the elusive bomber, who by then had killed two more people and maimed two others. The paper reported that the FBI believed the Unabomber (its code name) held a strong anti-technology and pro-environment philosophy, may have been born in the Chicago area and was probably adept at woodwork, given the intricately carved boxes into which some of bombs had been built. It was Linda (who declined to be interviewed for this article) who first noticed the similarities to her brother-in-law.

In September of that year, The Washington Post and the New York Times jointly published the manifesto the Unabomber had sent, along with his demand that it be printed in exchange for an end to his bombing campaign. David and Linda spent more than a month poring over each word, looking for clues in the massive diatribe that might lead back to Ted -- or exonerate him. They began to see patterns.

The manifesto contained phrases and ideas that were similar to things Ted had penned over the years. "Cool-headed logicians" -- David remembered that phrase from one of Ted's letters.

David loved his brother, but he knew he was sick and needed help. And yet, David believed, if Ted was the Unabomber, he might strike again. In November 1995, David wrote Ted one more time. David was worried about him. Could he come to Montana for a visit?

The response was frigid: "I am not suffering, sick or discouraged, and I don't know what indication you think you have that I am so. Get this straight . . . I DON'T EVER WANT TO SEE YOU OR HEAR FROM YOU . . . AGAIN."

And so they called a private investigator, a childhood friend of Linda's, and asked for help.

I think my brother might have some connection to this Unabomber, David told Susan Swanson, the in-

vestigator, during one of their phone conversations in late December 1995. David and Linda gave her some of Ted's letters and other writings and asked her to find an expert to evaluate them against the manifesto. David was haggard and exhausted from worry.

Swanson called Clint Van Zandt, a former FBI behavioral science expert she knew, and gave him typed copies of two handwritten letters David had given her. At David's insistence, she didn't tell Van Zandt who had written the letters or how she had come by them. She just wanted him to analyze what he read and compare it to the Unabomber manifesto.

Van Zandt pulled together two teams of analysts and set to work. A few weeks later he called Swanson. His words were urgent: Whoever gave her the letters needed to contact the FBI immediately.

David was devastated -- and frightened. What if his brother struck again? "My primary interest, all along, was to protect lives," David says softly as the evening darkness seeps further into the living room. He takes a sip of soda and continues. He knew his brother was sick, really sick, and needed to be protected. David couldn't bear the idea of the police cornering and trapping Ted like some wild animal, and he didn't want Ted hurt. He also didn't want Ted to know that it was David who had given him up.

Acting anonymously through a Washington lawyer, Anthony P. Bisceglie, David began a careful dance with the FBI. After extensive negotiations, the FBI promised to keep David's identity a secret and to give the family at least a day's notice before it moved in on Ted.

It was now time for David to break the news to his mother. In March 1996, after the two had breakfast together, David began pacing the floor of her apartment, not sure how to begin. Tears were streaming down his cheeks. Wanda watched in bewilderment. "David, what's the matter?" she asked him. "Well, it's about Ted . . . " he replied, and then told her the whole story, ending with, "I have notified the FBI . . . They are waiting to talk to you."

Wanda wouldn't believe it. Ted? He couldn't hurt anyone. She remembers looking at David, who was clearly in torment, and reaching over and hugging him. "Oh dear, what you have been going through," she said, and then told him, "You'll see, you'll see. He couldn't have done it. When this is fully investigated Ted will be exonerated."

Later that day FBI agents arrived and began sifting through Ted's letters home and other keepsakes. When the last agent finally left, it was dark. Mother and son sat alone in the living room and, as Wanda recalls, "we both wept. Yes, we wept."

And then late on the afternoon of April 3, 1996, David was in a staff meeting at the nonprofit agency where he worked as a counselor when he got an urgent call from Bisceglie. The FBI was about to serve a search warrant on Ted's Montana hovel. Get your mother and Linda and go home now.

What happened next is a blur. Wanda recalls that when David arrived at her apartment, he tried to call the FBI, irate that it hadn't given the promised advance warning, but could only reach answering machines. When an agent finally called back, she said there had been a leak to the media and the FBI now felt it had to move in on Ted with dispatch.

About an hour later, as David, Wanda and Linda huddled together in Wanda's apartment watching the television news, they were stunned to hear Dan Rather say that the elusive Unabomber had been "fingered by relatives." And then: "The first tip in the case came from Chicago, from Kaczynski's own family. Through a Washington attorney, a brother told the FBI he had uncovered evidence suggesting his sibling might be a suspect," the reporter covering the story told Rather.

The Kaczynskis were shattered. "We all felt so betrayed," recalls Wanda. "Linda was sitting there, I was sitting there and Dave was sitting there and we were all crying. Well, this is after we saw Dan Rather say this. I have never been able to watch Dan Rather since."

As the family watched in disbelief, Wanda remembers thinking, " 'I hope to God that they don't hurt him. I hope they don't have a shootout.' I'm thinking of Ruby Ridge and Waco and all of that mess that went on before."

And then it was over. Ted was in custody. The family went into seclusion to avoid the swarms of reporters and television cameras eager to pick over all details of their lives. They felt battered and alone.

David wanted to help Ted and make contact. Ted, though, through public defenders representing him, made it clear he wanted nothing to do with the family. At court hearings, he wouldn't even look David's way.

In May 1997, Attorney General Janet Reno announced that prosecutors would seek the death penalty for the Unabomber. David received the news by telephone from Bisceglie and started crying.

Wanda was as terrified for David as she was for Ted. She told people that it would be impossible for David to live the rest of his life feeling that he was somehow responsible for his brother's death. "David had such a burden. Oh, how terrible it would be for David if that happened," Wanda recalls thinking at that time. "It was a horrible thing. I thought of Ted lying on that gurney and being injected. It was horrifying to us to think that they would put him through that."

David knew he wouldn't be able to cope with that. "It would be very, very difficult to live with myself knowing that I had delivered my injured, disturbed brother over to be killed," he told people. For nearly the next year, David worked to persuade the Justice Department, and the public, that the death penalty was not justified for Ted -- he was mentally ill -- and that to pursue it would discourage other families from stepping forward as David had done. He traveled to Washington twice to appear before the Justice Department committee that decides which federal defendants should face the death penalty. He gave a speech and several media interviews to make the case that it would be unjust to give the death penalty to a man he portrayed not as an evil or malicious monster, but as a sick human being who needed help and who, underneath it all, had redeeming qualities.

And then, during the trial in January 1998, Ted tried to commit suicide. Wanda and David were living in a rented apartment in Sacramento near the courthouse where Ted was being tried when they heard the news.

Eventually, a government psychiatrist agreed with the findings of psychiatrists for the defense that Ted Kaczynski was suffering from paranoid schizophrenia. A deal was struck -- life without parole -- and Ted was spared, not in a way he would tolerate well perhaps, but he would live. David, who for days sat in a courtroom a mere 15 feet behind his older brother but was never graced with a word or even a glance from Ted, now had to begin picking up the pieces of his own life.

In the autumn of 1998, David fell into a malaise. He'd felt terribly despondent before, during the trial and especially when Reno announced she would seek the death penalty. This time, "life felt completely tasteless. I was sleeping and lying around and moping. It was like nothing I had ever felt before," David says now. "Linda tried to cheer me up . . . [but] it was as if I was wrapped in gauze and she was a distant voice. I heard what she was saying, I knew cognitively what it meant, but I had difficulty responding emotionally to it. Everything felt very flat."

Sometimes David found himself just imagining what it must be like for Ted in his cell. "There were moments when I pictured him caged like an animal in a system that he feared," he recalls. "But there was also the hope in my mind and heart that he was adjusting, receiving three meals a day and being treated with at least his essential human dignity intact."

Wanda was worried about David. "I thought, 'Oh my God, what if he breaks down over this, what if he can't survive this.' "

It's hard to pinpoint exactly when the post-trial depression began to lift, but at some point, after a few weeks, David the social worker, David the compassionate brother, realized that he had something more to do. Ted had hurt a lot of people. David felt a responsibility to make amends to the victims.

The Justice Department had offered a $1 million reward for information leading to the arrest of the Unabomber, and in August 1998 it had released the money to David and Linda. For David, it was "blood money" and the couple immediately pledged to donate the funds to Ted's victims and their families. "It was really a no-brainer when you think of all the difficulty, the anguish that went into this conflicted decision to turn in Ted," David recalls. "There was no way that we could have kept the money."

David and Linda sent out letters to the victims telling them that they could apply for the money. In the end, about half the Unabomber's victims responded. The funds began flowing out -- by the end of 1999, $680,000 had been paid out. David used some of the reward money to pay for the family's legal expenses, and some of it had to go to taxes.

David lobbied hard to get Congress to exempt the reward money from taxes so that he could give more away to the victims. "I went down to Washington and literally walked the halls, and I remember calling people on the phone and saying I was Ted Kaczynski's brother and people thinking it was a practical joke or something," David recalls. With the support of then-Sen. Daniel Patrick Moynihan, the bill passed the Senate, but it died in the House.

Giving away the money was an important step in his own healing, David now says. But when he thought about the maimed computer scientist, or the families of the dead advertising executive and the forestry lobbyist, he felt it wasn't enough. For his own peace of mind, David needed to do more.

After Ted's arrest, David had written letters to all his brother's victims, expressing his sorrow and regret. A few responded, with some even expressing appreciation for David's painful decision. Most, though, remained silent. And one victim couldn't be found. There was no address for Gary Wright, a computer shop owner in Salt Lake City who was injured by shrapnel in 1987 when he picked up an explosive-filled package in the parking lot behind his business. Then one day in late 1996 an investigator helping the Kaczynskis gave David a telephone number for Wright's home.

"He wasn't home so I left a message. It was very odd," David recalls. "You don't know what to say exactly." He left a brief message, saying he was Ted's brother, would like to talk and would call back. "It's intensely awkward, and you want to be respectful and somehow acknowledge the tragedy that in some strange way has joined and separated you, without saying the wrong thing, without increasing someone's pain."

A few days later, David tried again. Wright was washing the dinner dishes when the phone rang. As Wright recalls: "He said that he was sorry on behalf of his family. He was really genuine and sounded nervous. He later told me he was prepared for a blast of anger, but it didn't come. I told him that he can't carry that emotional burden for what someone else has done."

They talked for about 20 minutes. Wright was so kind and open and forgiving that when it was over David felt a deep sense of release. It was, as he puts it, "a real gift." David asked if it would be okay if he called again sometime, and Wright said, sure.

There were more telephone calls, and then in 1998 the two met as David was on his way home from Sacramento from Ted's trial. They spent two hours in a diner, over a late breakfast, talking about the case, Ted's illness, David's work and the whole ordeal for David and his family and the impact on Wright and his family. It was just the beginning of what was to turn into a real friendship and regular telephone conversations.

For Wright, the contact with David and his family has brought a certain peace: "The fact there was a great family there has brought back a sense of humanity for me and helped me put some finality to this. It brought almost a sense of calm to a situation that was so complex. I think that people like myself respect David for his ability to feel and understand their grief."

The relationship with Wright, though, was the only bond David was able to establish with a Unabomber victim, despite his efforts. While some responded graciously to David's efforts to reach out to them, none seemed interested in further contact. David would have to find some other way to make amends.

In 1999, he received an invitation from Survivors of Homicide, a group of families of murdered children and other loved ones, to be the keynote speaker at its annual anti-violence conference. The group had approached David after its head, Samuel Rieger, whose daughter Melanie was murdered by a boyfriend, saw David on the "Today" show and was struck by how understanding he was toward the Unabomber's victims and their relatives.

"I thought how unusual it was. You never hear perpetrators' families saying how much they care for the victims' families and expressing pain and suffering for them," Rieger recalls.

David readily accepted the invitation. These people were not Ted's victims, but they were like them. "I was very nervous about going there to speak. It was an education for me . . . to realize the kind of terrible emotional impact that a killing has on a victim's family. So even though I was not talking or interacting with any of Ted's victims, I was in a sense, in that they were like surrogates for that. In other words, I knew it would have to open me in some ways to the horror of what Ted had done and there would be, in a sense, no escaping it."

It was a full house when David arrived at the auditorium at Naugatuck Valley Community College, in Waterbury, Conn., for the conference. About 750 people had shown up to hear the brother of the Unabomber, the one who had turned him in. In the front row sat about 30 members of the homicide survivors group.

David talked for about 45 minutes, about building "emotional bridges" between families on both sides of such tragedies, about how he still considered his mentally ill brother to be a valuable human being, about the commonality of his family's suffering with the torment of many of those at the conference.

When he was done, he was greeted with applause. Several people came up and hugged him.

"He is really one of us. He has a lot of pain and suffering and he is genuine, and given what we have suffered, we don't need any baloney stories," Rieger says. "He just comes and says, 'Let's help each other.' He comes with an open mind."

David, too, felt the common thread. "There are losses involved that are never going to be healed entirely. These losses are going to be defining us for the rest of our lives."

Last year when David returned to the survivors group's conference, a man whose brother had been murdered pulled David aside and told him that his speech the year before had changed his life. The man had begun participating in a program to talk to violent inmates in an effort to understand them, and it had helped him feel compassion instead of just hatred. He'd begun to heal. That, David says, "is one of those things that makes me cry. I was moved by this sense, by seeing that there are these seeds in the world of good that can grow out of something bad."

But there were more jarring moments. Through his anti-death-penalty work, David had gotten to know Bill Babbitt, who, like David, had a brother who was mentally ill. And he, too, turned his brother in when he suspected him of a murder. Babbitt's brother Manny was a decorated Vietnam veteran whose lawyers pleaded that he get life in prison because he was schizophrenic and suffering from post-traumatic stress syndrome. In the end he got the death penalty. And David, who along with Linda had campaigned hard for Manny's life to be spared, was one of the few outsiders standing at the grave in Wareham, Mass., to bury Manny after his execution.

"For once I was standing on the periphery and I saw Bill's mother break down and beginning to wail and throw herself on the ground and Bill attempting to comfort her," says David, growing emotional while recounting the funeral. "I realized that was what I had feared to go through."

David had come to believe more strongly than ever, as he talked more and more to families of murder victims, that taking a life to avenge a death did not bring healing to anyone. It just created more victims, more sorrow. And there was the whole question of its unfair application -- Manny Babbitt, who was black, killed one person and got death; Ted killed three, injured 23 and got life in prison.

David began speaking out, not just about cases similar to his, like Bill and Manny Babbitt, but about all death penalty cases. Through the Survivors of Homicide group he met Marc Klaas, who had been catapulted into the forefront of death penalty advocates after the murder of his 12-year-old daughter, Polly. Not long ago, Klaas proposed that they do a speaking tour together, presenting both sides of the issue. The Unabomber's brother would be a big draw, Klaas thought. David accepted.

He explains: "The passion I felt about how it was so wrong to execute Ted has led me to other questions about this criminal justice process that is shallow, that is bureaucratic, that is not humane and that turns a deaf ear to cries of pain and, even at times, the voice of truth."

And so it was that one evening this March, David looked out at some 400 students packed inside a lecture hall at Creighton University in Omaha and told them, "We owe some consideration to how this affects other people. I don't think that we can ignore their pain." David added, "I think the truth is that we must dehumanize someone before we kill them. This is what the Nazis did in the Holocaust."

He would never want to be seen as minimizing what his brother had done, he told them, but life in prison without the possibility of ever again being free could be seen as more severe than capital punishment because murderers would be forced to live with the consequences of their crimes for the rest of their lives.

"The impulse for revenge is a serious problem for human beings," he said. "We are not God. We tend to confuse justice with revenge."

Klaas was having none of it: "Nothing wrong with a little social vengeance . . . Ladies and gentlemen, evil exists. And when we find it exists, we have to eradicate evil, one way or another. It is a layer of protection between us and them."

Since September 2000, the two men, now friends, have held three other capital punishment debates -- in Plattsburgh, N.Y., New Orleans and Orlando. They have also appeared together on "The Early Show" on CBS. David has also been a guest on the "Sally Jessy Raphael Show" and Court TV and given a number of speeches decrying the death penalty. He has talked to New Yorkers Against the Death Penalty, the National Coalition to Abolish the Death Penalty, Connecticut public defenders, the New York State Bar Association and the Bruderhoff Communities, an international faith-based movement that has taken a stand against capital punishment.

"It seems like one thing has led to another, and that I want to bring some greater good out of something that was unimaginably bad," David says.

In this way, David has made a peace of sorts with the fact that his relationship to Ted, and what David had to do, will color his life forever. It's no longer such an oppressive idea, David has found; it can sometimes be something positive.

Like when the 15-year-old boy piped up from the back seat of the Prizm and asked, Dave, why'd you turn him in? He looked the boy in the eye and told him that sometimes you have to do the right thing, even if it's incredibly painful. Sometimes you have to realize that although the consequences of an act can be hard to live with, not acting would be even worse.

"If Ted had gone out and killed another person, I would have felt personally responsible," he told the boy. "I would have felt that I could not live with myself anymore, that I would have blood on my hands."

David writes to his brother three or four times a year, reminiscences sometimes, recountings of jokes he's heard, a gentle bemoaning of the loss of contact. The letters are never that long. Last Christmas, he sent Ted the book Ishmael about a gorilla who speaks telepathically, telling a philosophical tale about the fall of human beings from their natural state. David figured that the theme would be of interest to Ted.

He has never tried to explain to his brother why or how he decided to turn him in to the FBI. "I guess it has to do with my past experience with Ted and an understanding of how his mind works," David says. "If I were attempting to justify myself it would trigger a sort of debate or an argumentativeness. And it's almost like he would analyze what I've said and try to show that it is insincere in some way or find the fallacy in it."

A couple years ago, a Time magazine interview with Ted Kaczynski suggested just that. The jailed Unabomber said David had been motivated purely by sibling rivalry. David found Ted's interpretation of his action extremely upsetting.

Wanda writes to Ted at least every other week and sends newspaper articles and magazines stories about the environment and other topics she thinks may interest him. She also sends him some money to buy provisions in the prison.

"I write him short notes and tell him that I think about him all the time and that I hope he is well," Wanda says. "In one of the first letters, I said, 'I want you to know that I have always loved you and always will.' "

Ted has not responded to any of the letters. They don't hold that against him. They just hope that one day he will pick up a pen or make a telephone call to get in touch. And they'll be waiting. "I don't let myself think about the possibility of never hearing from him or never seeing him again," his mother says.

David, too, hopes one day to reconnect with Ted. "Time heals to some extent, but the bond I feel with Ted doesn't disappear. Sometimes I'll remember the good times -- a backpacking trip, a softball game, or talking at night in his cabin -- and my sense of loss is very poignant. Those times we shared mean a lot to me and so I hold on to them . . . Different as we may seem in some respects, Ted was a major influence in my life, and so, inevitably, he remains a part of me."

In the meantime, David doesn't dwell on the whole thing like he used to. In fact, he and Linda have signed a contract for an undisclosed sum with Disney, which wants to do a movie about the Unabomber case. And the Unabomber ordeal has come to occupy a smaller space in his consciousness. "Gosh, Linda and I used to talk about 'it' like we had nothing else to talk about but 'it.' This went on until maybe even last year. It seemed like somehow it was dominant in our lives. It was tiresome but we both gravitated back to it. It wasn't just me. She would somehow come back to it. Certainly, that is less persistent now."

He has become a Buddhist, like his wife. He says he finds truth and comfort in Buddhism's beliefs -- that all human beings are interconnected and that compassion and the sanctity of human life should be one's guiding principles. Buddhism has also, he says, brought him closer to Ted. He concludes each half-hour meditation by dedicating it to his brother, in what Buddhists call merit of practice. Linda does, too, when the couple meditate together. "He is distant and remote, but this makes him more present to me, a bit closer on some plane," David says. "This process of meditation is in a sense a very intimate process and I guess it makes me feel less helpless, too."

These days he can even acknowledge that Ted was onto something in his manifesto. Technology can be dehumanizing. "There is a tremendous threat to the soul of human beings. And I think so much depends on some ability to resist it, to keep your life spiritually rich."

And so life, slowly, is moving on. David and Wanda and Linda often have dinner together, or go out to an occasional movie. Every week or so David takes his mother shopping, since she no longer drives. They celebrate the holidays together, and David and Wanda mark Ted's birthday by talking about him and all that has happened to the family.

Together, they attend meetings of a support group of people with mentally ill relatives. David says the group has been particularly helpful for Wanda, who often questions her parenting because of what happened to Ted. Was there something she did that turned him so cold, made him so strange?

"These are people who have been through what she has, meaning that they question themselves and feel helpless, as well. I think most people in the group are aware that there is no rational basis for feeling guilty, although it is somewhat unavoidable. I think every parent of a mentally ill person carries some sense of responsibility, some sense of guilt."

Wanda, sitting across from her younger son at the dinner table, adds, "One of the things that I have wondered about is whether there was anything that I did that was so different and so heinous that he could do this. What did I do? I keep going over and over this in my mind."

David's own guilt is also complex. Could he have done more as a brother? Could he have helped prevent what happened? "There are times when I have looked back and thought obviously I could have been a better brother," David says.

Wanda doesn't let him go there: "Oh, David, you were a very good brother."

His job as a social worker at Equinox Inc., a youth shelter and outreach group in Albany, has been particularly therapeutic. Who knows what young Ted is out there in need of help? Who might change if someone takes the time to reach out? "If there is some desperate kid out there at risk of being violent and doing terrible things that will destroy their lives and the lives of other people, if I could help that kid, it would seem more meaningful to me than before, because I would see a chance to help that I missed with Ted," he says.

He was working at Equinox before the Unabomber case took over his life six years ago. It took him a while to get back. He finds different ways to reach kids. Not long ago, he and a group of teenagers put on a program at a local mall stressing nonviolence and personal responsibility. The program, which included skits by the kids, kicked off two weeks promoting nonviolence in and around Albany in the face of a recent surge in gang-related shootings. Shoppers stopped to watch the show and the teenagers seemed to get a lot out of it.

Sometimes, it is the kids who help David. One afternoon last spring as he was driving a 14-year-old boy home from the library, where David had been helping him with science homework, the boy began to talk about how down he was feeling about himself. Sitting next to David in the front seat, he said he was being unfairly singled out as a troublemaker at school.

David couldn't let that go unanswered: Don't ever let anyone convince you that you're not a good kid, he told the boy.

And the boy, who knew about David's role in the Unabomber case, looked at him and said, "Don't let anyone ever convince you that you did anything wrong."

Serge F. Kovaleski, who now writes about D.C. politics for The Post, covered the Unabomber case. He will be fielding questions and comments about this article at 1 p.m. Monday on www.washingtonpost.com/liveonline.