The Varieties of Religious Experience is the edited form of William James’s Gifford Lectures on natural theology, which he delivered at the University of Edinburgh, Scotland, between 1901 and 1902. James intended these lectures to more completely assess religion through a philosophical lens, but health problems forced him to curtail that goal, leaving the lectures largely a description of the many different ways people directly and immediately experience religion. These include ways like healthy-mindedness, saintliness, conversion, and mysticism.

This work is one of the foundational texts of the field of psychology of religion, which developed alongside modern approaches to experimental psychology dating to the 1890s. The Varieties of Religious Experience has been in print since its publication and has an established place in the western canon.