Clifford Howard's work on "Sex Worship" is a broad overview of phallic worship and related topics which serves as a fairly proper introduction to all of the more specific subtopics of this formerly taboo school of mythological study- the cultus arborum, serpent veneration, the lingam and yoni of Hinduism, and so forth.Carefully avoiding the explicit and obscene, the book is flatly academic, and well written, dwelling often on Greece, Rome, and then-modern India. Works such as this one completely changed anthropological and religious discourse over the course of just a few short decades at the end of the 19th and beginning of the 20th centuries.
