A book that I always meant to read but never got around to is God is not One; The Eight Rival Religions that Run the World by Stephen Prothero. I gather that what he's doing in that book is pushing back against a trend that we see with Epicureanism all the time--the "they're-all-basically-saying-the-same-thing" crowd. Joseph Campbell is often cited as an example of the other camp.
Prothero in his own words:
QuoteAccording to the Dalai Lama, "the essential message of all religions is very much the same." From this perspective, popularized by "perennial philosophers" such as Aldous Huxley, Joseph Campbell and Huston Smith, all religions are beautiful and all are true. The prevailing metaphor portrays the world's religions as different paths up the same mountain. "It is possible to climb life's mountain from any side," writes Mr. Smith, "but when the top is reached the trails converge."
This is a seductive sentiment in a world in which religious violence can seem as present and potent as God. But it is dangerous, disrespectful and untrue.