Susan Horowitz Cain, born in 1968, is an acclaimed American writer and lecturer renowned for her groundbreaking work on the power and potential of introverts. Her influential book, Quiet: The Power of Introverts in a World That Can't Stop Talking, published in 2012, challenges the cultural bias favoring extroversion and highlights the significant contributions of introverts to society. Cain's dedication to introverts led her to co-found Quiet Revolution in 2015, an organization dedicated to offering support and resources in the realms of children, lifestyle, and the workplace.

In 2016, Cain expanded her advocacy for introverts with the release of Quiet Power: The Secret Strengths of Introverts, which addresses the unique qualities of introverted children and teenagers, aimed also at helping their educators and parents understand and nurture these traits. Her recent work, Bittersweet: How Sorrow and Longing Make Us Whole (2022), delves into the role of sorrow and longing in the human experience, advocating for the acceptance of these emotions as catalysts for profound feelings of beauty, wonder, and transcendence.