Acclaimed by William James as "an addition to psychology of first-rate importance, " this pioneering work constitutes a classic modern study of the mystical experience. Author Richard Maurice Bucke, a distinguished progressive psychiatrist, explores the phenomenon of transcendent realization, or illumination. Bucke draws upon his firsthand experience of a life-altering insight to explore the theory of cosmic consciousness, an advance in mental evolution with the potential to raise existence to a higher plane. As valuable today as it was upon its 1901 publication, this landmark survey treats illumination from the standpoint of psychology, as a rare but definite and well-documented mental condition. It cites instances of sudden enlightenment experienced by mystics, philosophers, writers, and artists throughout history, noting an increasing frequency of episodes consistent with an evolutionary trend. Numerous case studies offer intriguing, real-life particulars of people and their personal epiphanies — from Buddha, Jesus, and Mohammed, to Dante, William Blake, Walt Whitman, and lesser-known individuals. A work of uplift and promise, this book offers readers a vista of extraordinary possibilities and a renewed capacity for hope and wonder.