William James was a member of the generation that founded American psychology and philosophy; his work in both these fields placed James in the forefront of the intellectual and cultural ferment that marked late 19th century America. In this classic work, he turned his attention to the psychology of religion. He examines such phenomena as conversion, repentance, mysticism, and saintliness; his observations and theoretical speculation are accompanied by personal accounts of religious experience. James believed that organized religion stifled the natural religious impulse; his belief in personal experience as the only true source of religious feeling led to a remarkable tolerance for extreme forms of religious behavior.

First published in 1902, The Varieties of Religious Experience initiated the psychological study of religion, paving the way for Freud and Jung as well as for clinical and paranormal branches of psychology. Written with humour and erudition, its theories of conversion, saintliness, ecstasy and mysticism continue to provoke controversy and enquiry. The book remains the best introduction to James's thought, demonstrating his characteristic insistence upon the importance of personal experience and his almost devotional respect for the mysteries of the human mind. Richly illustrated with personal accounts of belief and possession, intoxication and near-death experience, it is of central importance not simply to an understanding of religions, but to modern psychology and psychiatric medicine. The Routledge Centenary Edition, entirely reset from the original 1902 edition, is prefaced with a specially commissioned foreword by the author's grandson, Micky James, and with new introductions from James specialists Eugene Taylor and Jeremy Carrette. It also includes a new and expanded index.