While shamanism occurs in virtually every culture on the planet, manifesting itself in religious traditions both ancient and modern, both "primitive" and sophisticateed, the shaman remans eminently individualistic, idiosyncratic, and enigmatic, standing ever apart from organized ecclesiastical institutions while still performing important functions for the psychic and religious life of the culture.
"... he is believed to cure, like all doctors, and to perform miracles of the fakir, like all magicians, whether primitive or modern. But beyond this, he is a psychopomp, and he may als be priest, mystic, and poet."-Eliade
He further defines the shaman as a manipulator of the sacred, whose main function is to induce ecstasy in a society where ecstasy is the prime religious experience.
... the novice shaman must undergo an initiatory ordeal before he can attain the status of a full shaman.