The Big 5 is a metric for evaluating personality based on five traits: openness to experience, conscientiousness, neuroticism, extroversion, and agreeableness. This model of personality is one of the most respected amongst psychologists and provides a nuanced interpretation because of its spectrum grading. King endorses this approach as a way to broadly get to know people’s way of behaving and interacting with the world.

This psychological phenomenon makes people favor information that seems to prove their judgment correct and dismiss evidence that goes against their formed opinion. King considers confirmation bias a hazard when assessing others, as it might cause one to make inaccurate first impressions. According to King, checking one’s first impressions and balancing them with logic is a way to overcome this bias.

The Enneagram is a personality typology developed by philosopher Oscar Ichazo, whose ideas were later expounded on by psychiatrist Claudio Naranjo. Enneagram types provide another model for interpreting personality based on prominent traits and values, though it is not a system endorsed by psychologists. The types are described as figures, such as the peacemaker or the individualist, and there are a total of nine.

The Four Temperaments is another personality typing system. It was developed by psychologist David Keirsey and is widely popular, though some scholars have dismissed it as pseudoscience. This understanding of personality divides people into four broad groups: the guardian, the artisan, the idealist, and the rational.

Psychoanalyst Sigmund Freud observed people’s strong motivations to avoid pain and pursue pleasure, calling this the “Pleasure Principle.” Read People Like a Book identifies this as a baseline motivation to bear in mind when interpreting others’ behavior.

Psychology professor Abraham Maslow came up with the framework of a “hierarchy of needs” to explain different levels of human motivation, from physiological fulfillment, to safety, to love and belonging, to self-esteem, and finally, self-actualization. This is another lens that King offers for interpreting behavior.

The Myers-Briggs model of personality was invented by writers Katharine Cook Briggs and Isabel Briggs Myers. This framework identifies an individual as one of 16 “types” based on where they fall along four axes: introversion or extroversion, sensing or intuiting, feeling or thinking, and perceiving or judging. For instance, an ESFP person would be extroverted, sensing, feeling, and perceiving. King suggests that this typology can be useful in understanding others despite its lack of evidentiary support.

Theory of mind refers to the ability to understand what someone else knows or feels based on one’s interactions with them. King refers to theory of mind when explaining how people instinctively create a model of another person’s “cognitive and emotional realities” (10). While this is useful, King cautions the reader that their inferences can never capture the full complexity of someone’s inner world.