Note: I have Steet's permission to post a review on the book here! 

Compared to the movie, the book itself is far more detailed and explains things better (I would personally suggest reading the book first if you haven't seen the film) than the film did. For example, I didn't realize that the cinder block in the garden was their winter home. In the film, this detail was not mentioned, which left me confused to as of why they apparently returned to the cinder block every year. That question was answered right at the beginning of the book! 

In my opinion, I think the characters in the book are developed better than the characters in the film. Take Brutus for example. In the book, instead of chasing Mrs. Frisby away when she enters the rosebush, he questions her and asks her to leave, even after Mrs. Frisby tries to reason with him. However, he DID follow her out to a degree before returning to his post. There's also another character, Arthur, who didn't make it into the film (I wish he would have! I don't see how Don didn't have room to squeeze him in). He's the engineer of the colony, and it's he who makes moving Mrs.Frisby's home possible. Then there's Nicodemus. In the film, he's portrayed as a very old and magical rat (which I don't mind at all, although it's a bit strange) who only spends time with himself (as it appears, anyway). In the book, in a few chapters, he explains in great detail to Mrs. Frisby on how he and others arrived at NIMH, and how they were tested and grew smarter over a long period of time.

To sum this up, I quite enjoyed this book, and I would defiantly read it again!