Based on 20 months of fieldwork among the Azande people of South Sudan, Evans-Pritchard's work became the founding text in the anthropology of witchcraft. Although the book had little impact when it first appeared in 1937, its popularity grew after World War II and its influence on anthropology is still strong nearly 80 years later. Evans-Pritchard wholeheartedly supported an emerging belief in the importance of first-person fieldwork rather than the library-bound anthropology favored by previous generations. Most importantly, Witchcraft transformed the anthropology of knowledge by insisting that the supernatural beliefs of 'primitive' societies fulfilled clear social and moral functions.