Born May 22, 1942 in Chicago. While still an infant, Kaczynski had a severe allergic reaction to medication. He was hospitalized in isolation for several weeks and allowed infrequent visits from his parents, during which they couldn't hold or hug their child. The once-happy baby reportedly was never the same.

Grew up in Evergreen Park, a suburb of Chicago, where his mother helped fire her oldest son's intellectual drive. The pair would sit on the front stoop and read Scientific American together.

When he was about 12, Kaczynski dropped off a caged animal at neighbor Dorothy O'Connell's home for her to watch while his family camped. He carried with him a copy of "Romping Through Mathematics from Addition to Calculus."

Friends and neighbors have said the boy's genius was apparent but his social skills severely lacking: "I would see him coming in the alley. He'd always walk by without saying hello. Just nothing," said Dr. LeRoy Weinberg, a former Kaczynski neighbor. "Ted is a brilliant boy, but he was most unsociable ... This kid didn't play. No, no. He was an old man before his time."

But classmates said Kaczynski did horse around, albeit with chemicals, not toys: "We would go to the hardware store, use household products and make these things you might call bombs," junior high classmate Dale Eickelman told the Daily Southtown, an Illinois newspaper, in 1996. "Once we created an explosion in a metal garbage can."

While other young people listened to rock 'n' roll, Ted preferred classical music by Vivaldi and Bach that "had mathematical perfection and symmetry," his brother, David, said in a January 1997 interview. "I can't ever recall him singing songs or listening to lyrics."

Education: Skipped two grades, graduating from high school in 1958 at the age of 16; earned bachelor's from Harvard University in 1962. Earned master's and Ph.D. in mathematics from the University of Michigan at Ann Arbor.

Professors have recalled Kaczynski as a brilliant graduate student able to solve complicated equations that stumped other math experts. Socially, he was a loner.

Career: Hired as an assistant professor of mathematics at the University of California, Berkeley, on a two-year contract that started in the fall of 1967. Resigned without explanation in 1969.

"He said he was going to give up mathematics and wasn't sure what he was going to do," John W. Addison, then department chair, wrote in 1970 to Kaczynski's dissertation adviser at the University of Michigan. "He was very calm and relaxed about it on the outside. We tried to persuade him to reconsider, but our presentation had no apparent effect."

Addison called Kaczynski "almost pathologically shy," a man who had made no close friends in the department.

Calvin Moore, vice chairman of the department in 1968, said that given Kaczynski's "impressive" thesis and record of publications, "he could have advanced up the ranks and been a senior member of the faculty today."

In a financial affidavit filed June 25, 1996, Kaczynski reported that he was unemployed, having last worked in 1979, when he earned $760 per month.

Published: Papers with such daunting titles as "Boundary Functions and Sets of Curvilinear Convergence for Continuous Functions" in prestigious math journals.

Life in Montana: With his brother, David, bought land in Lincoln, Mont., in 1971. Lived in a 10-by-12-foot ramshackle cabin he'd built himself with no electricity or running water. Mostly unemployed, surviving on a few hundred dollars a year, chopped wood for heat, hunted deer, food from his garden and cans of Spam and tuna. Rode a bike for transportation, sometimes dressed in overalls and a straw hat; in the winter used chains on his bicycle tires for traction or hitched a ride with a mail truck.

Teresa Brown, a sales clerk at Garland's Town & Country store in the heart of Lincoln, described him as being "polite, shy, very nice."

"Someone you'd never suspect, I guess, she said. "He was always alone. ... I didn't think he had any friends. I don't even think he had a job, just a little lonely hermit up there."

Occasionally, he would visit with Carol Blowars, a real estate broker who lived a quarter-mile away, and bring gifts to her and her husband, George. "He talked about his garden," Blowars said. "He brought all kinds of things, carrots and spinach."

"He was very highly educated, way beyond a level of anything I would read," said Linda Bordeleau, a librarian's assistant. "He read literary works. A lot of the books he wanted had to be ordered because they were extremely intellectual works. He would bring back his books and I would ask him: You can read and understand this stuff? I couldn't."

Communications: Instructed family members to draw a red line under the stamp if a letter contained urgent information. Such a letter came in 1990, after his father's suicide. Kaczynski reportedly was upset because he felt the note didn't warrant the urgent symbol. After his brother's marriage in July 1990, Kaczynski wrote his brother a venomous letter stating, in capital letters, that he never wanted to see or hear from David or any other member of the Kaczynski family again. He has refused any contact with his mother or brother since his arrest.

Unrequited romance: Smitten with Ellen Tarmichael, a supervisor at a foam-rubber plant in Addison, Ill., where he worked while living with his family briefly in 1978. The two saw each other a few times socially before Tarmichael, who has since said there was no romance between the two, told Kaczynski that she no longer wanted to see him. Kaczynski made rude comments about Tarmichael at work and wrote rude limericks, which he hung around the plant until his supervisor — his brother, David — fired him. Kaczynski worked another job before moving back to Montana in 1979.

Residence: Curiously, since 1982, listed in Harvard's alumni directory as Afghanistan. Now confined to a Sacramento County jail cell with a toilet, sink, running water and electric lights — comforts not found in his Montana cabin.

Recognition: Named on of the 25 Most Intriguing People of 1996 by People magazine.

Family: His terminally ill father, also named Theodore, committed suicide in 1990. His mother, Wanda, now lives in New York. Both were warm and nurturing "talkers," who while their sons were growing up spoke often of the value of education and of the need to do what is right. "They weren't rigid disciplinarians and by and large I don't think they needed to be," David Kaczynski has said. "Neither of their children ever created problems in the community or problems in school."

Pleaded guilty: Jan. 22, 1998, in exchange for life in prison with no chance for parole; will be formally sentenced May 15, 1998.

On the plea bargain: "We feel it is the appropriate, just and civilized resolution to this tragedy, in light of Ted's diagnosed mental illness," his brother, David Kaczynski, said.