Written in response to John Locke's "The Reasonables of Christianity" (1695) "Christianity Not Mysterious" asserts that there is nothing in religion that was above reason and that no Christian doctrine could properly be called mysterious. The book attracted a large number of replies and responses, one of which is included in this volume. Browne's "Letter" reveals the state of Irish Protestant attitudes toward deism or dissent at the end of the 17th-century.