The words, a nagual, nagualism, a nagualist, have been current in English prose for more than seventy years; they are found during that time in a variety of books published in England and the United States,4-* yet are not to be discovered in any dictionary of the English language; nor has Nagualism a place in any of the numerous encyclopædias or “Conversation Lexicons,” in English, French, German or Spanish. This is not owing to its lack of importance, since for two hundred years past, as I shall show, it has been recognized as a cult, no less powerful than mysterious, which united many and diverse tribes of Mexico and Central America into organized opposition against the government and the religion which had been introduced from Europe; whose members had acquired and were bound together by strange faculties and an occult learning, which placed them on a par with the famed thaumaturgists and theodidacts of the Old World; and which preserved even into our own days the thoughts and forms of a long suppressed ritual.