Pratchett has done his work. I believe him when he says that he read loads about rats before beginning this. But not only the rat part is accurate. When he describes rat writing (pictograms, could be hieroglyphic-like), it parallels the history of the development of human writing. The rats in this story provide a kind of microcosm of how human society might have developed; their dreams of utopia do not come from out of the blue. The rats have their version of a holy book, a keeper of the flame, and of course their characters are all very different and sometimes conflict. Baseness, greed, and corruption all figure in the story, and the rats need to discover how to deal with this new threat called EVIL (as the book's back cover will also tell you).
Although the mentally-mutated (smart) rats naturally figure prominently in the story along with a mentally-mutated cat (Maurice), I think that it also works as an allegory. You can read this story either for face value or more deeply. In the latter way, I think that Terry Pratchett critiques current society. It's funny that reading about rats would make one question humanity, but that's what happened to me!
In a way this book is about having dreams and trying to fulfill them, and getting disillusioned along the way but not giving up. However, it has no morality overtones and despite its seriousness, it is also pretty funny (take the tap-dancing rat named Sardines, for instance). The story ends on a happy note too but it isn't overly saccharine. In a way, it's like pop philosophy and a good story rolled into one.
I was also able to read this story without knowing anything at all about Discworld.
Terry Pratchett is a true science fiction genius. THE AMAZING MAURICE AND HIS EDUCATED RODENTS takes you on a journey into the minds of rats, cats, and even dogs, and reveals what they think of humans, each other, life, and the world in general. Maurice is a character whom will stick in the minds of all, young and old, as will his entertaining companions, Dangerous Beans, Peaches, Darktan, Hamnpork, and even the stupid-looking kid. A must-have book for all who enjoy a good science fiction novel here and there. Or if you're just looking for an entertaining novel featuring a gang of exciting, talking animals.
Erika Sorocco