Short answers, pulled from the story.
Shamanism is a spiritual practice in which a practitioner called a shaman interacts with the spirit world through altered states of consciousness such as trance. The shaman directs spirits or spiritual energies into the physical world to heal, to perform divination, or to otherwise aid human beings.
The Modern English word shamanism derives from the Russian word шаман, which itself comes from a Tungusic language, possibly the southwestern dialect of Evenki or from Manchu. The term has also been linked to the Tungus root meaning "to know" and to the Sanskrit word śramaṇa, though both connections are debated.
The word shaman was introduced to English speakers in 1698 through a translation of Adam Brand's account of a Russian embassy to China. The Dutch statesman Nicolaes Witsen had earlier carried the term to Western Europe in his 1692 book about Siberia.
Anthropologists criticize shamanism as a Western construct applied from the outside that cannot capture the variety of Indigenous spirituality. Alice Kehoe argues it enables cultural appropriation and reinforces the noble savage stereotype, and Hakan Rydving has called for abandoning the terms shaman and shamanism as scientific illusions.
Shamans often say they were called through dreams or signs, while others claim inherited powers, and training generally takes years. Many undergo a shamanistic initiatory crisis involving physical illness or psychological breakdown, an experience captured in the wounded healer archetype.
The earliest burial interpreted by some researchers as that of a shaman dates to the early Upper Paleolithic, around 30,000 years ago, in what is now the Czech Republic. In November 2008 researchers announced a 12,000-year-old shaman burial in lower Galilee, Israel, where an elderly Natufian woman was buried with 50 complete tortoise shells, a human foot, eagle wings, and a cow tail.
Traditional Indigenous shamanism is believed to be declining worldwide, though isolation preserved it among peoples like the Nganasan and the nomadic Tuvan, whose estimated population is 3000. Revitalization efforts are led by former shamans among the Sakha and Tuvans, and since the early 2000s ayahuasca tourism around Iquitos, Peru has created a new economic niche for practitioners.