威廉·詹姆斯（William James，1842—1910）美国本土第一位哲学家和心理学家，也是教育学家，实用主义的倡导者，美国机能主义心理学派创始人之一，也是美国最早的实验心理学家之一。1875年，建立美国第一个心理学实验室。1904年当选为美国心理学会主席，1906年当选为国家科学院院士。2006年，詹姆斯被美国的权威期刊《大西洋月刊》评为影响美国的100位人物之一（第62位）。

Hailed as "one of the greatest philosophical minds of all time" by English philosopher Alfred North Whitehead, William James is widely recognized as one of the most influential figures in twentieth-century Western philosophy and as the founder of the psychology of religion.

An immediate bestseller upon its publication in June 1902, The Varieties of Religious Experience weaves together acute observations with simple anecdotes to argue that individual religious experiences, rather than the tenets of organized religion, are what form the backbone of religious life. The book explores all sides of religous life, from repentance and conversion to mysticism and the value of saintliness. Written with James' characteristic humor and skill, The Varieties of Religious Experience sounds the depths of what he termed "Man's Religious Appetites.

The old clich that Henry James wrote novels as though they were philosophical treatises whereas William James wrote philosophic treatises as though they were novels, while unfair to Henry, describes . . . the William James of The Varieties of Religious Experience, very well. Believers and unbelievers (and semibelievers) will continue to find in it both a resource and a challenge," wrote religion scholar Jaroslav Pelikan.