In psychology, trait theory is a major approach to the study of human personality. Trait theorists are primarily interested in the measurement of traits, which can be defined as habitual patterns of behaviour, thought, and emotion. According to this perspective, traits are relatively stable over time, differ among individuals, and influence behaviour. This book presents data on personality trait research including narcissistic and borderline personality traits and their relationship with childhood abuse experiences; personality disorders and subjective well-being; male body image and eating disorders; using personality traits in relation to entrepreneurship research; the relationship between lay conceptions of intelligence, personality traits and others.