William James 
The Varieties of Religious Experience 

First published in 1902, ‘The Varieties of Religious Experience’ by William James, a psychologist and philosopher who taught at Harvard, contains, in edited form, a series of natural theology lectures called the
Gifford Lectures which he delivered at the University of Edinburgh in the two years leading up to its publication. 

The lectures argue about the nature of religion and the tendency of modern religious studies to ignore the importance of science in their research. The lectures, immediately acclaimed, are considered part of the
Western canon. The lectures also contain hints of James’s developing notion of pragmatism, which he later synthesised in his 1907 book, ‘Pragmatism’.