This book offers a historical overview of mysticism in the world's major religious traditions. Beginning with a chapter on the nature of mystical experiences, then turns to a discussion of mysticism's prehistory in shamanism and the early use of psychedelics. The possible role of mystical experiences among early Greek philosophers (including Socrates and Plato) is subsequently addressed, followed by chapters on mysticism in Judaism, Christianity, Islam, Hinduism, Buddhism, Daoism, and a variety of present-day iterations, including New Age mysticism, secular mysticism, and the scientific study of mystical experiences. An appendix covering popular misunderstandings of mystical experiences and mysticism is also included. Written in a clear, accessible style, this book is suitable for students of religion and philosophy as well as general readers interested in mysticism and the world's variety of mystical traditions.