Unabomer (both: yo͞o`nəbŏm'ər), name given by the FBI to the elusive perpetrator of a series of bombings (1975–95) in the United States that killed 3 and wounded 23. The targets were mainly academics in technological disciplines, airline executives, and executives in businesses thought to affect the environment. Fifteen bombs—most mailed, some hand-placed—exploded, and one was defused. In 1995 the Washington Post and New York Times published the Unabomber's long, rambling manifesto after he pledged in return to end the bombings. A year later the FBI, acting on information from his brother David, arrested Theodore J. Kaczynski (1942–), a reclusive former mathematics professor, at his isolated cabin in Montana. In Jan., 1998, Kaczynski pled guilty to federal charges related to the bombings; later that year he received four life sentences plus 30 years in prison.