 In late 1967 , Kaczynski became an assistant professor of mathematics at the University of California , Berkeley , where he taught undergraduate courses in geometry and calculus . He was also noted as the youngest professor ever hired by the university , but this position proved short @-@ lived . Kaczynski received numerous complaints and low ratings from the undergraduates he taught . Many students noted that he seemed quite uncomfortable in a teaching environment , often stuttering and mumbling during lectures , becoming excessively nervous in front of a class , and ignoring students during designated office hours . Without explanation , he resigned from his position in 1969 , at age 26 . At the time , the chairman of the mathematics department , J. W. Addison , called this a " sudden and unexpected " resignation . In 1996 , vice chairman Calvin Moore 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 . " 
