Abstract Spiritual experiences have occurred in people around the world and throughout history, up to and including the present day. The founders of every major religion described them, philosophers since the ancient Greeks have pondered them, and according to recent Gallup polls, about 30% of people in the United States and the United Kingdom still report them. A century ago, in The Varieties of Religious Experience, philosopher and psychologist William James famously analyzed accounts of these experiences and raised questions for future scientific study. What triggers these events? How are the brain and body affected? How do these brief moments have such lasting effects? Now, modern science has some answers. This book, The Varieties of Spiritual Experience: Twenty-First Century Research and Perspectives explores scientific breakthroughs on spiritual experiences from the fields of psychology and neuroscience. Readers are invited into laboratories around the world to learn about the methods scientists use to study these elusive yet profound inner events. Survey questions included throughout the book allow readers to discover how scientists would classify various experiences. The book also features examples of spiritual experiences drawn from a diverse set of personal accounts. For many people, spiritual experiences rank alongside marriage and childbirth as among life’s most meaningful moments—this book builds on William James’s theoretical foundation and provides the basis for a scientifically informed contemporary understanding of these profound and mysterious experiences.