This study is the first operational exploration of the thinking and behavior of all 83 persons known to have attacked, or approached to attack, a prominent public official or public figure in the United States since 1949. In addition to data about each attack or near-attack and each subject's demographic and background characteristics, information was gathered about each subject's ideas and actions in the days and weeks before their attacks or near-lethal approaches. Questions were examined about each subject's movement from the idea of attack to actual attack, motives, selection of targets, planning, communication of threat and intent, symptoms of mental illness, and significant life experiences. In every case, the attack or near-attack was the end result of an understandable, and often discernible, process of thinking and action. Implications for protectors, investigators, and researchers are discussed.