Anders Behring Breivik carried out a massacre in Norway on July 22, 2011, killing a total 77 persons and leaving 42 others severely wounded. He detonated a bomb in Oslo and then drove to the island of Utøya, where he shot and killed youngsters gathered at a youth camp. The authors performed an analysis of Breivik's writing style in his extensive manifesto which he published hours before the attacks, and also referred to the two psychiatrists' reports. The first report concluded that he suffered from paranoid schizophrenia. The authors concurred with the second report. Breivik seemed to be a person with narcissistic personality disorder, whose grandiosity might have caused him to be regarded initially as mentally deranged; however, closer examination revealed his deliberate attempt to methodically indoctrinate and deceive potential readers, to alarm potential targets and to terrorize a nation.