American psychologist William James documented diverse mystical and ecstatic experiences, including drug-induced ones, in his Gifford Lectures. Drawing from global traditions, he validated altered states as psychologically significant. It mattered by bridging science and spirituality in the modern era.

James influenced modernist poets like T.S. Eliot and stream-of-consciousness writers exploring consciousness. His work inspired Beat Generation and psychedelic literature, legitimizing ecstatic themes in 20th-century poetry worldwide.