Regardless of one's views about religion, I consider Terry Pratchet's Small Gods an essential book. A great satirical novel about how institutionalized religion manipulates and deceives people and religions' race in order to attract as many believers as possible.

As reads on the back cover: "Religion is a controversial business in the Discworld. Everyone has their own opinion, and indeed their own gods - who come in all shapes and sizes. In such a competitive environment, there is a pressing need to make one's presence felt. And it's certainly not remotely helpful to be reduced to be appearing in the form of a tortoise, a manifestation far below god-like status in anyone's book. In such instances, you need an acolyte, and fast - preferably one who won't ask too many questions..."
Isn't this the ideal acolyte for any organised religion?
AMSG