"INFJ (Introversion, iNtuition, Feeling, Judging) is an acronym used in the Myers-Briggs Type Indicator (MBTI) publications to refer to one of the sixteen personality types. The MBTI assessment was developed from the work of prominent psychiatrist Carl G. Jung in his book Psychological Types, which proposed a psychological typology based on his theories of cognitive functions.
From Jung's work, others developed psychological typologies. Well-known personality tests are the MBTI assessment, developed by Isabel Briggs Myers and Katharine Cook Briggs, and the Keirsey Temperament Sorter, developed by David Keirsey." - INTJ on Wikipedia.