How many introverts do you know? Chances are you know more than you think.

According to Susan Cain, author of Quiet: The Power of Introverts in a World That Can’t Stop Talking, the number of people who consider themselves introverts is between one third and one half. In her book, Cain delves into the psychology behind introversion and discusses how the importance of extroversion in American culture can affect introverts.

The definition of an introvert, according to Cain, is someone that prefers “to devote their social energies to close friends, colleagues, and family. They listen more than they talk, think before they speak, and often feel as is they express themselves better in writing than in conversation. They tend to dislike conflict. Many have a horror of small talk, but enjoy deep discussions.”

In exploring the psychology of introverts, Cain alternates between presenting the studies and findings of noted scientists and discussing the personalities of well known figures or her clients. She clearly did a lot of research for her book, not only in analyzing the conclusions of psychologists but also in forming her own conclusions based on countless interviews of introverts of all ages and demographics.

In the first few pages of the book, Cain talks about a supposed client of hers named Laura, an introverted corporate lawyer who struggled to be heard in the midst of extroverts in the workplace. I say supposed client because later Cain reveals that this ‘Laura’ is actually herself; before she became a writer and consultant she was a reserved lawyer who gradually overcame her fears of public speaking and conflict.

Throughout the book, Cain discusses the struggles of her actual clients and highlights the quiet strength, leadership, and brilliance of famous introverts like Rosa Parks, Eleanor Roosevelt, Mahatma Gandhi, and Steve Wozniak. These in depth personality profiles make her ideas more personal to the reader and allow the reader to better understand the conclusions she presents about the strengths of an introverted personality.

Besides talking about specific individuals, Cain talks in depth about the studies of noted researchers such as Jerome Kagan, Elaine Aron, and Carl Schwartz. Sometimes she spends too much time summarizing these psychologists’ research, but their studies were applicable to her ideas on introversion and interesting in terms of their methods and conclusions. Kagan conducted research following a set of children from infancy to adolescence and found that he could predict which children would become more reserved introverts or more outgoing extroverts based on their reactions to stimuli as infants. Schwartz, a protégé of Kagan, uses fMRI, functional magnetic resonance imaging, to measure which parts of the brain are active when thinking or performing tasks.

Although Cain presents a number of interesting theories and conclusions, there is too much information for the reader to take away concrete advice that is helpful to introverts trying to come out of their shell or extroverts trying to learn how to better interact with introverts. The book is appealing mostly to introverts because it analyzes why introverts act like they do and how they can adjust to jobs or other environments that require public speaking or stressful social interactions. The part of the book that is most applicable to extroverts comes at the end when Cain details the best ways to communicate with introverts.

Overall, Quiet was an interesting, if somewhat dry, book that raised questions about how our personalities affect the way we see and interact with the world around us. For those interested in psychology or considers themselves introverts, this would be an engaging and worthwhile read.