Shamanism is a spiritual practice centered on a shaman, an individual who enters altered states of consciousness (trance) to interact with the spirit world for healing, divination, and community guidance, acting as a bridge between physical and spiritual realms. It's a diverse, ancient tradition found globally, predating organized religion, using drumming, chanting, and other techniques to journey to non-ordinary realities for insight, soul retrieval, and restoring balance, say sources like Britannica and Wikipedia.