James Mooney was an American ethnologist and folklorist whose life's work helped preserve Native American traditions at a moment when many of them were under intense pressure from U.S. expansion and assimilation policies. Born in Indiana in 1861, he developed an early fascination with Indigenous cultures and later joined the Bureau of American Ethnology, where he spent years traveling, living among communities, and recording languages, ceremonies, myths, and historical memory with unusual care and sympathy for his era. His most important achievements came from his painstaking documentation of Native religious life, especially his influential study of the Ghost Dance movement and the events surrounding the Sioux conflict of 1890, which remains a landmark in the history of Native resistance and federal policy. Mooney's writing is valued not only for its detail but also for its insistence that Native people were active interpreters of their own worlds, not mere subjects of outside observation. His work often explores spirituality, cultural survival, misunderstanding between peoples, and the devastating consequences of colonial violence—themes that still resonate today in conversations about sovereignty, historical justice, and the preservation of endangered cultures. Though some of his methods reflect the limits of his time, his legacy endures as one of careful listening and cultural documentation, and modern readers continue to find in him a vital witness to a crucial chapter of American history. He is especially rewarding for readers interested in Native American history, anthropology, religious movements, and the contested making of the American West.