Many books give detailed descriptions of the sixteen personality types defined by Katherine C. Briggs and her daughter, Isabel Briggs Myers. Most of the books provide little or no theory to support their descriptions, and the descriptions seem subject to dismissal as readily as personalities defined by astrological signs. Three books, however, give the necessary theoretical backbone to Briggs and Myers’ type structure.

The first is Gifts Differing: Understanding Personality Type by Isabel Briggs Myers, first published in 1980. Myers wrote the book as a way to communicate her mother’s findings that expanded Carl Jung’s original theory of psychological type dating from the early 1920s.

In Gifts Differing, Myers theorizes that everyone prefers one of two ways of perception and one of two ways of decision-making. She theorizes further that everyone has a favorite between these two favorites. If I am a “feeler,” it is because I have put my four ways of perception and judging through an unconscious tournament bracket, and “feeling” won:

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This tournament takes place in the central letters of an MBTI (Myers-Briggs Type Indicator) inventory. Feeling would win out for four types – ENFJ, ESFJ, ISFP, and INFP – in this tournament. The first two types I mention are “extroverted feelers,” and the last two are “introverted feelers.” Sensing and intuition (the two ways of perception) and thinking (the other way of decision-making) each have their four adherents among the types, too.

If I am an introvert, you may not be able to tell that “feeling” won. You may see me predominately by my auxiliary function (the runner-up in my tournament), which I “extrovert.” An extrovert is easy to know, Myers posits, because she extroverts her dominant function. What you see, then, is what you get. The extrovert’s auxiliary function is left to run her inner life.

Briggs and Myers add the “Judging/Perceiving” dichotomy to Jung’s theory to indicate which function the people around us see. My “J/P” score indicates which of my two favorites the world sees predominately – my favorite way of perception or my favorite way of decision-making (judging).

I’ll stick with Myers’ feelers as examples of the J/P dichotomy. For these four types, it makes sense that the extroverts are “J”s and the introverts are “P”s. The “J” in ENFJ and ESFJ points to the “judging” function, which in the case of these two types is feeling. The “E” indicates that these two types extrovert feeling. Similarly, the “P” in ISFP and INFP points to the perception function. Therefore, an ISFP extroverts his auxiliary function of sensing and the INFP extroverts his auxiliary function of intuition. Both types introvert feeling, their dominant function.

Based on the introversion/extroversion dichotomy and based on dominant functions, Myers groups the sixteen types into eight pairs. Sticking with our primary example, one pair is introverted feelers. Despite their different auxiliary functions (the ISFP’s is sensing and the INFP’s is intuition), introverted feeling types share a strong sense of inner values and artistic expression that come with introverted feeling.

Myers differentiates her mother’s work from Jung’s by the great emphasis Briggs places on the auxiliary function. Nevertheless, Myers puts little emphasis on the auxiliary function in her groupings of the sixteen types. How an introvert runs his outer life or how an extrovert runs his inner life is secondary to who these people really are, based on their dominant functions.

Myers’ detailed description of each of the sixteen types flows naturally from these formulations. Unlike most books on Myers-Briggs personality type, Myers’ book is grounded in theory and offers more than interesting personality type descriptions.

Two of the more theoretical and enlightening books based on Briggs and Myers’ theory are Please Understand Me II by David Kiersey and I’m Not Crazy, I’m Just Not You by Roger R. Pearman and Sarah C. Albritton. Kiersey’s book, probably the most popular book on personality type, regroups the types somewhat.

Kiersey groups Briggs and Myers’ sixteen types into four temperaments: the artisan, the guardian, the idealist, and the rationalist. He is unabashedly results-oriented in his groupings and applies different questions to different types to arrive at the groups.

In making up his groups, Kiersey first asks (as we have seen Briggs and Myers do), how do we prefer to perceive, by sensing or intuition? But he proceeds to ask the sensors and the intuitives different questions. He asks, what do sensors do with their perceptions? Do they organize them (judging), or do they continue to take them in (perceiving)? The answer to those questions makes a sensor either an “SJ” (guardian) or an “SP” (artisan). With regard to the intuitives, however, he asks, how do intuitives judge (make decisions) – objectively (thinking) or subjectively (feeling)? The answer to that question makes an intuitive either an “NT” (rationalist) or an “NF” (idealist).

Kiersey’s haphazard theory helps him match his four temperaments with more archetypal personality theory (Greek, Native American, Elizabethan) and so his four temperaments may be more readily identifiable to us than Myers’ eight categories.

Pearman and Albritton also have their own groupings of the types. They find that types with the same “cognitive cores” (the middle two letters of the four-letter MBTI score) have more in common with each other than with other types. Pearman and Albritton go beyond Myers’ analysis of the dominant and auxiliary members of the cognitive core by studying our relationship to our “tertiary” as well as our least used members of this four-member core.

Pearman and Albritton urge us to stay in touch with our tertiary and least used members in order for us to lead balanced lives and to avoid having these untrained forces rise up and surprise us with all of the force suppression spring-loads into us.

I’m Not Crazy also uses Myers’ groupings, and it creates other new groupings in order to squeeze more juice out of type theory. To their credit, the authors avoid overly detailed descriptions of the sixteen types, finding that “too often (in our experience about thirty-five percent of the time) the detailed descriptions simply do not work for individuals though they may in fact verify that the MBTI inventory sorted their preferences correctly.”

Other books on Myers-Briggs personality theory provide fascinating and often dead-on descriptions of the sixteen types, but offer little or no insight into the underlying theory. Among the best of these are Otto Kroeger and Janet M. Thuesen’sType Talk at Work and Sandra Krebs Hirsh and Jean Kummerow’s Life Types.

Please Understand Me II and I’m Not Crazy explore interesting sides of personality theory by reshuffling the deck of types and redefining the suits. Written earlier, Myers’ book still surpasses them both, principally because it amounts to more than a reshuffle. Myers expands the deck from Jung’s eight types to sixteen, based on her mother’s groundbreaking research.