David West Keirsey (; August 31, 1921 – July 30, 2013) was an American
psychologist, a professor emeritus at
California State University, Fullerton, and the
author of several books. In his most popular publications,
Please Understand Me (1978, co-authored by Marilyn Bates) and the revised and expanded second volume
Please Understand Me II (1998), he laid out a self-assessed
personality questionnaire, known as the
Keirsey Temperament Sorter, which links human behavioral patterns to four temperaments and sixteen character types. Both volumes of
Please Understand Me contain the questionnaire for type evaluation with detailed portraits and a systematic treatment of descriptions of temperament traits and personality characteristics. With a focus on
conflict management and cooperation, Keirsey specialized in family and partnership
counseling and the coaching of children and adults.