Terry Pratchett’s Small Gods is a good place to start in the pantheon of the Discworld books. That’s the reason we chose it, rather than one of the many others, to read in book club. There are a couple of places where having read some of the other books would give some additional depth (the librarian, or Death), but it’s not necessary for the enjoyment of the story. There are a lot of Discworld books. To get something of a picture of how they’re all related, try the Reading Order Guide (link from BoingBoing).
I remember reading Discworld books when I was studying physics, but then somehow got out of the habit (probably because they weren’t readily available in Germany where I was living at the time). So I was glad to be reminded of just how good a read they can be. Small Gods is a parody of religions, gods, and inquisitions. It tells the story of a small god (the definition being one that doesn’t have many followers and therefore doesn’t have much power) and his symbiosis with the one true believer. Along the way, Pratchett neatly pokes fun at organized religion, the Inquisition, philosophers, and lots of other things. It’s the sort of book you read for the snide asides as much as the storyline. It can be read at lots of levels; you can just read and enjoy the story or think about the deeper implications for comparative religions. We had fun discussing the relationship between Om and Brutha in terms of who needed whom the most. Both Om and Brutha change and learn during the book’s events; Om becoming less vengeful (although while he’s in tortoise form there’s not much he can do to carry out any vengeful actions) and more thoughtful through being maltreated (running gag: “there’s good eating on a tortoise” within earshot of him) and through Brutha’s bargaining power (he is, after all, the reason that Om is sentient although it takes him a while to figure that out).
All in all, worth trying if you haven’t already, even if you don’t usually read fantasy or science fiction. Just don’t blame me if you get hooked on the series.