Why do some beliefs become extinct while others adapt and flourish? James shows us how genetic evolution and cultural evolution, though operating at different rates, are one and the same. Recent science has gone a long way toward explaining the origin of religious belief in evolutionary terms, but Craig James has cracked open the mystery of its tenacity. Religion does not exist for us, it exists for its own sake. Like a selfish gene or a parasite, the religion virus catches a free ride in the minds of our species, infecting our history and culture.