I have created a new page for Joseph Campbell's Thou Art That book. It has an exerpt from the book that includes his well known radio interview about 'what is a myth'.
of the interview: It made me reflect that half the people in the world think that the metaphors of their religious traditions, for example, are facts. And the other half contends that they are not facts at all. As a result we have people who consider themselves believers because they accept metaphors as facts, and we have others who classify themselves as atheists because they think religious metaphors are lies....Joseph Campbell
Here is the link to the page