Pop-psychology books trigger the skeptic in me. Who, I wonder, is this stranger with slim credentials who’s lecturing me on how to become a better person? And how can I trust that the people he cites—Jim H., Mary G.—aren’t composite characters, or even fictional?

So it was a pleasant surprise to encounter a psychology book by an expert—a neuropsychiatrist—telling the stories of identified people, written with compelling style, on an intriguing subject: Samuel Barondes’s Making Sense of People: Decoding the Mysteries of Personality.

This book summarizes everything researchers now know about the human personality. It applies these current insights to help us cope with the difficult people in our everyday lives (the rigid boss, the recalcitrant lover, the mysterious prospective son-in-law). And Barondes, a professor and director of the Center for Neurobiology and Psychiatry at the University of California, San Francisco, has the credentials to enlighten us. For illustrative examples he chooses people we all know about, ranging from Bill Clinton and Barack Obama through Ralph Nader, Bobby Fischer, Steve Jobs, and Oprah Winfrey. And all the details he cites—in substantial explanations—are sourced from the subjects’ own memoirs and solid biographies.

The personality, he tells us, is built up from four elements: traits, patterns, genes, and life history. These elements are constantly working on one another. Understanding them can help us make educated guesses on questions both crucial (“Will my daughter’s fiancé ever settle on a career?”) and mundane (“If I give my Luddite sister a Kindle for her birthday, will she just return it?”).

Researchers and statisticians (always named and cited in the book) agree that there are actually only five basic personality traits (“the Big Five”). Everybody possesses some combination of these traits, each of which exists on a continuum: a person is (1) an extrovert or an introvert, or something in between, (2) agreeable or antagonistic, (3) conscientious or impulsive, (4) neurotic or emotionally stable, and (5) open to new experience or conservative and resistant to change.

Understand Your Own Personality

The Big Five are more complex than they appear at first, and the best way to get a comfortable understanding of them, says Barondes, is to take a web-based personality questionnaire called the IPIP, devised by psychologists at Penn State. It’s free, anonymous, and takes about 20 minutes. (Click on IPIP; when the page opens, check the two boxes giving the site your permission and press send. It will take you to the questionnaire.) You’ll get an automated e-mail report that compares your Big Five scores with those of others of your age, sex, and nationality who have already taken it. Understanding yourself helps you to comprehend others.

I did this and found it enlightening, especially in the Big Five’s subcategories: There are, for instance, several different kinds of extroversion, a trait in which overall I was high (I do “prefer to be around people much of the time”). But as I saw, there are different types of extroversion, and while I was high in “friendliness and gregariousness,” my level of “assertiveness and activity” was only average, my “excitement-seeking” was low (I won’t be white-water rafting any time soon) and, to my great unpleasant surprise, I don’t seem to be very cheerful, either.

While we all display some measure of the Big Five traits, only a limited number of people exhibit the Top Ten patterns, which are the “potentially troublesome personality patterns” cited by the American Psychiatric Association in its Diagnostic and Statistical Manual (commonly known as DSM-IV). These patterns are what you’d better watch out for in sizing up someone. While the psychiatrists, appropriately, list each pattern in neutral jargon, Barondes supplies the judgmental language we favor in everyday speech, and his list hits home: An “antisocial” pattern means crooked; “avoidant” means cowardly; “borderline” means unstable; “compulsive” means rigid; “dependent” means freeloading; “histrionic: is vain; “narcissistic” is selfish; “paranoid” is untrusting; “schizoid” is aloof; and “schizotypal” is bizarre.

Some of these patterns have, oddly enough, been employed in moderation by successful people we’ve heard of. Barondes uses Ralph Nader as an exemplar of the paranoid pattern “suspicious rather than trusting”—a pattern that underlay Nader’s successful campaign to expose corruption in industry and government; Nader also displayed the narcissistic pattern common among political leaders, but this got out of hand in his 2000 presidential campaign.

Can People Change?

Perhaps the most important question we face in our daily lives is, “Can people change?” Am I beating my head against the wall, for example, in trying to persuade my boss to let employees work from home using Skype? How will Dad come to accept my gay brother? To figure out the answers, we need to know which parts of personality are hard-wired— genetically programmed—and which are flexible and open to modification. As Barondes reports, studies contrasting identical twins (who have all the same genes) with fraternal twins (who have half the same) show that heritability of the Big Five traits is about 50 per cent— and this holds true equally for identical twins reared apart and those reared together. We don’t, however, have a “selfish gene” or an “angry gene.” What we have is a combination of hundreds of different genes and their variants that act on each other in complex ways to produce our unique heritage of traits.

The traits we inherit—as Barondes pointed out to me when I chatted with him after reading the book—are in the form of predispositions to be, say, more or less outgoing or agreeable. Some are obvious to our parents when we’re infants (this baby is friendly, that baby is anxious in new situations) and others come on line during adolescence, but these predispositions evolve through constant dialogue with the world we’re in. The psychologist Jerome Kagan’s work with shy and friendly children revealed that about half the children he’d studied as toddlers and then as 7-year-olds maintained their demeanor in adolescence, and only 15 per cent changed significantly. What does modify a personality somewhat as we grow up are the experiences we have with our families, our friends, and the culture we live in. By the time we are young adults we have built up a life story, our own account of the events that have made us what we are.

So whether your father will come to accept your gay brother depends, for example, on the combination of how open he is to new experience, whether he would put himself out to make sure the whole family gets along, whether he has a compassionate nature, and perhaps his capacity for anger and insecurity, put together with how gay people were regarded in the place where he grew up and whether family solidarity was essential. In adulthood our basic temperament remains the same, but life crises in particular can change our values. By now you certainly have some idea of your father’s disposition, but laying it out systematically and asking yourself a few new questions via Barondes may help you figure out how best to handle him.

Sizing up bosses, colleagues, and difficult neighbors should require more effort—and understanding, as Barondes puts it, “What’s their story? What are they after? How do they see themselves in terms of their past, present and future?” could be useful indeed.

“When you first start drinking wine,” Barondes told me, “ you just say, ‘I like this, I don’t like it,’ but if you become somewhat educated in the difference between a Pinot and a Cabernet and the difference between a Cabernet from France and a Cabernet from California, you’ve gained a system for understanding what you taste.” The people in our lives are more important than the wine, and his book gives us a sophisticated insight into what they’re about.