A Guide to the Development and Use of the Myers-Briggs Type Indicator . The 3rd Edition of the Manual was published by CPP in 1998. The essence of the theory is that much seemingly random variation in behavior is actually quite orderly and consistent, being due to basic differences in the way individuals prefer to use their perception and judgment. Perception involves all the ways of becoming aware of things, people, happenings, or ideas.
Judgment involves all the ways of coming to conclusions about what has been perceived.
If people differ systematically in what they perceive and in how they reach conclusions, then it is only reasonable for them to differ correspondingly in their interests, reactions, values, motivations, and skills. The MBTI is based on Jung's ideas about perception and judgment, and the attitudes in which these are used in different types of people. The MBTI contains four separate indices. Each index reflects one of four basic preferences which, under Jung's theory, direct the use of perception and judgment. The preferences affect not only what people attend to in any given situation, but also how they draw conclusions about what they perceive.