And, as is generally the case around the time a prophet is expected, the Church redoubled its efforts to be holy. This was very much like the bustle you get in any large concern when the auditors are expected, but tended towards taking people suspected of being less holy and putting them to death in a hundred ingenious ways. This is considered a reliable barometer of the state of one's piety in most of the really popular religions.
True masterpieces are rare in series fiction. Even when they are very good, novels in a series usually have an element of predictability that keeps them short of real greatness. Small Gods, however, is a work of series fiction which ranks with the best humorous fiction ever written.
Most of Terry Pratchett's novels are set in a fantasy place called Discworld. It is flat and one can fall off the edge. It is supported by four elephants who stand on the back of a gigantic turtle. Magic works, and the laws of physics are strangely twisted. Pratchett has used this background to create some excellent humorous novels involving various recurring characters.
Small Gods is set long before the time period in which most of the novels occur; aside from a throwaway time-travel scene, the only character in common with the other novels is Death, who is eternal. This separation allowed Pratchett to do something very different, creating a novel which is at once humorous and philosophically expressive.
In Discworld, there are many gods. Their power depends upon having believers; a god with no believers fades into a powerless, wandering spirit or dies. The Great God Om has a powerful church, yet has only one real believer, a novice monk named Brutha. Drained of supportive power, he finds himself trapped in the body of an ordinary tortoise who can communicate only with Brutha.
At first, Brutha is extremely simple-minded. He has a photographic memory; this and the severely restricted life of the monastery have made it unnecessary for him to think. But being in regular communication with a god can do strange things to a person -- things which even the god may not expect.
The Exquisitor, Deacon Vorbis, finds Brutha's talent and his guilelessness very useful. Vorbis is a very well-drawn personification of authoritarian fanaticism, and the humor running through the book doesn't keep him from being frighteningly evil. As Brutha eventually observes, Vorbis changes people to be like him, even when they are fighting against him. Brutha begins by trying to serve two very different and contradictory masters, Om and Vorbis; by the end, he has grown to a full understanding of both of them, and realizes that neither one can be his master. Indeed, he learns to stand up to his god when he knows that Om is wrong.
But Om also learns, as he comes to grips with being part of a world which had previously been simply a source of worshippers for him. He constantly faces physical danger, as well as the possibility of losing his last follower. His condition provides a telling commentary on whether people need gods or gods need people.
The Omnian Church holds that the world is spherical and goes around the sun, and those who believe otherwise risk being tortured and killed as heretics. But Discworld really is flat, and the philosophers of Ephebe -- a land with a strong resemblance to ancient Greece -- aren't afraid to say so. The watchword of the heretics is "The Turtle Moves!" Aside from providing some fun, this reversal helps to shake up the reader's thinking, giving a reminder that what is important is to find out what really is true, regardless of what "everybody knows."
British humor is often marked by intense cynicism. Douglas Adams and Monty Python laugh as a desperate response to a world without any sense. Pratchett shows a cynical side, but always combines it with real warmth. In Small Gods he carries this further than in any other book of his that I've read, laughing at religious authoritarianism to show how unnecessary it is, and creating a tribute to the human spirit at its best.
If you read only one Discworld novel, this should be it. However, if you haven't read any Pratchett and think you might be interested in his work, I suggest starting with one of his other novels, such as The Color of Magic or Maskerade. Those books will introduce you to his universe and provide a background which will help in understanding Small Gods. And if you are a Pratchett fan and just haven't gotten to this particular book yet, get it immediately!