Cain holds a bachelor’s degree from Princeton University and a law degree from Harvard Law School. She is the author of four books. In addition to this one, she has written two others about introversion, Quiet Power: The Secret Strengths of Introverts (2016) and Quiet Journal: Discover Your Secret Strengths and Unleash Your Inner Power (2020). The former is a book for children and teenagers, with sections devoted to school, socializing, hobbies, and the home. The latter is intended as a companion to the book this guide examines, containing some basic information about introversion and many exercises that include journaling. It is designed for both introverts and extroverts to learn more about themselves and heighten awareness of their specific preferences and qualities. Cain’s most recent book is Bittersweet: How Sorrow and Longing Make Us Whole, published in 2022.

Before becoming a writer, Cain worked as an attorney at an international Wall Street law firm. After that, she founded and ran her own consulting company that focused on negotiation strategies. In the Introduction, she describes doing her job well at the law firm, but disliking intense, nerve-racking negotiations. While she preferred to avoid conflict, in such situations she realized that she could hold her own and that her calm, organized approach based on ample preparation was quite effective.