William James's (1842-1910) masterful treatise on the psychology of individual religious experience was originally composed for the prestigious Gifford Lectures delivered at Edinburgh University in 1901-1902. James's gift for distilling the essential ingredients of the religious experience from the great mass of details is evident in every chapter. Taking the approach that extreme manifestations of the religious temperament give us more insight into the subject than the routine features of worship and ritual, he discusses many intriguing accounts of remarkable religious experiences grouping these experiences into broad types: healthy-mindedness, the sick soul, the divided self and the process of its unification, conversion, saintliness, and mysticism. He also discusses the distinctions between religious experience and philosophy; psychological theories concerning the origin and nature of religious belief; and the overall value of religion to human well-being.