The Varieties of Religious Experience, by Harvard University psychologist and philosopher William James, comprises his edited Gifford Lectures on natural theology, which were delivered at the University of Edinburgh, Scotland, between 1901 and 1902. The lectures explore the psychology of private religious and mystical experiences, using a range of examples to identify commonalities in such experiences across traditions, including those of of such diverse thinkers as Voltaire, Emerson, and Luther. Soon after its publication, the book entered the Western canon of psychology and philosophy and has remained in print ever since. James wrote that his object was two-fold: 'first, to defend 'experience' against 'philosophy' as the real backbone of the world's religious life; and second, to make the reader believe that the life of religion is mankind's most important function.' He famously redefined religion as 'the feelings, acts, and experiences of individuals in their solitude, so far as