Shamans are individuals from traditional, pre-modern societies who mediate between their community and the world of the spirits. In order to travel to the domain of the spirits they enter a trance-like state, often by dancing, music, or a psycho-active plant. Shamanism is a widely spread practice, ranging from the Mongolian steppes to indigenous people of the Americas. While shamanistic practices will vary across cultures, in all shamanistic societies, it is presumed that the world is peopled by spirits and that proper ceremonial communion with these spirits will heal mental and physical illness, bring favorable weather conditions, regulate social harmony, etc. There is an emphasis on the ecstatic trance state as a condition of personal transformation. Moreover, an individual’s internal mental states are seen to be caused by—or at least subject to— outside forces, such as the spirits of ancestors, animals, or aspects of nature.