Personality assessment, in its broadest sense, includes any technique that is used to describe or make inferences about the characteristic traits, attitudes, beliefs, values, needs, motives, emotional states, coping styles, or aspirations of an individual. Personality assessment can take many forms, including an Internet dating questionnaire, an epitaph, a letter of recommendation, a psychodiagnosis, an integrity test administered as part of an employment application, and a psychobiography based on a historical record. For the present purposes, however, three major functions of personality assessment will be considered: assessment in the service of basic research and theory explication; assessment in applied psychology, including therapeutic, organizational, and forensic settings; and assessment in self-exploration. These different functions of personality assessment determine the personality characteristics to be measured and the instrument or method to be used. Personality characteristics constitute a fuzzy set, populated by constructs as diverse as extraversion, physical attractiveness, creativity, sexual orientation, gender, ...