Voodoos and Obeahs: Phases of West India Witchcraft by the Jesuit anthropologist Joseph J. Williams (1875-1940) offers a careful documentation of the history and ethnography of Voodoo and reveals the connection of both Haitian Voodoo and Jamaican Obeah to snake worship (ophioletreia). This work goes into great depth concerning the New World-African connection and is highly recommended if you want a deep understanding of the dramatic historical background of Haitian and Jamaican magic and witchcraft, and the profound influence of imperialism, slavery and racism on its development.