please understand me: character and temperament types (first published in 1978 as please understand me: an essay on temperament styles) is a psychology book written by david keirsey and marilyn bates which focuses on the classification and categorization of personality types. the book contains a self-assessed personality questionnaire, known as the keirsey temperament sorter, which links human behavioral patterns to four temperament types and sixteen character types. once the reader's personality type has been ascertained, there are detailed profiles which describe the characteristics of that type.