This paper describes the Myers-Briggs Type Indicator (MBTI), developed by I. Myers and K. Briggs (1940s) to assess personality type. Based on Jungian theory, the MBTI has become a tool for identifying the 16 different patterns of action into which every person fits. The 16 personality types are based on patterns of: (1) extraversion-introversion; (2) sensing or intuitive preferences; (3) thinking or feeling personalities; and (4) preference for structure or spontaneity. This paper reviews the evidence for reliability and validity for the MBTI and discusses administering the instrument. Uses and applications are also described. (SLD)