This excerpt from the book "The Dark Side of Personality" examines the nature and implications of several so-called "dark" personality traits, including narcissism, callousness, Machiavellianism, sadism, spite, sensation seeking, urgency, distractibility, perfectionism, and authoritarianism. The authors explore the adaptive and maladaptive aspects of each trait, reviewing relevant research on the traits' development, measurement, and relationship to various psychological disorders.