Although Susan Cain‘s Quiet (2012) may be the best known of the introversion resources/books, the following are some additional suggestions.

I. Books on Introversion

The Myers-Briggs Type Indicator (MBTI) can only be administered by certified practitioners, but a book by David Keirsey, Please Understand Me II: Temperament, Character, Intelligence (1998), offers a quick test, the Keirsey Temperament Sorter, that gives results similar to the MBTI. Keirsey gives detailed descriptions of each of the 16 types. Introversion is one of the key traits analyzed.

Additional books:

• Marti Olsen Laney, Psy.D., The Introvert Advantage: How to Thrive in an Extrovert World (2002)
• Laurie Helgoe, Ph.D., Introvert Power: Why Your Inner Life is Your Hidden Strength (2008)
• Sophia Dembling, The Introvert’s Way: Living a Quiet Life in a Noisy World (2012) and Introverts in Love: The Quiet Way to Happily Ever After (2015)

II. Article on Introversion

Possibly my favorite resource is an article by Jonathan Rauch entitled “Caring For Your Introvert: The Habits and Needs of a Little-Understood Group” (The Atlantic), March 2003.

Although tongue-in-cheek, the many good points in this piece have resonated with tons of people since its publication. Some excerpts:

• Introverts are not necessarily shy…Introverts are also not misanthropic, though some of us do go along with Sartre as far as to say ‘Hell is other people at breakfast.’ Rather, introverts are people who find other people tiring.
• For introverts, to be alone with our thoughts is as restorative as sleeping, as nourishing as eating. Our motto: ‘I’m okay, you’re okay–in small doses.’
• Extroverts have little or no grasp of introversion. They assume that company, especially their own, is always welcome.
• The only thing a true introvert dislikes more than talking about himself is repeating himself.
• We tend to think before talking, whereas extroverts tend to think by talking…
• The worst of it is that extroverts have no idea of the torment they put us through. Sometimes, as we gasp for air amid the fog of their 98-percent-content-free talk, we wonder if extroverts even bother to listen to themselves.

Rauch’s concluding remarks offer a (naturally) cheeky response to the following question: How can I let the introvert in my life know that I support him and respect his choice?

First, recognize that it’s not a choice. It’s not a lifestyle. It’s an orientation.

Second, when you see an introvert lost in thought, don’t say, ‘What’s the matter?’ or ‘Are you all right?’

Third, don’t say anything else, either.

III. A Test to Measure Introversion and a Chart

Scott Barry Kaufman in Scientific American introduces a test that purports to measure four different aspects of introversion based on previous academic findings of Jennifer Odessa Grimes. Go to the above-linked article and scroll down to “What Kind of Introvert Are You?” to take the test.

When you score your results you’ll have a number for each type. It’s not about the highest score being your type—rather, each score indicates how much of that type is part of your introversion.

For a quick read, go to this popular Huffington Post article by Lindsay Holmes, who provides an illustrated chart, “Dr. Carmella’s Guide to Understanding the Introverted,” by artist Roman Jones.