Psychologist Woo-kyoung Ahn devised a course at Yale called "Thinking" to help students examine the biases that cause so many problems in their daily lives. It quickly became one of the university's most popular courses. Now, for the first time, Ahn presents key insights from her years of teaching and research in a book for everyone. She shows how "thinking problems" stand behind a wide range of challenges, from common, self-inflicted daily aggravations to our most pressing societal issues and inequities. Throughout, Ahn draws on decades of research from other cognitive psychologists, as well as from her own groundbreaking studies. And she presents it all in a compellingly readable style that uses fun examples from pop culture, anecdotes from her own life, and illuminating stories from history and the headlines.