Mrs. Frisby and the Rats of NIMH by Robert C. O'Brien. 1971.

There’s a certain sameness to rodent-themed books, I’ve noticed. Velveteen Rabbit (ok, not quite, but ...), Ralph and the Motorcycle, Borrowers. Most have a lot of “critter skittering about for food” along with lots of scurrying, scraping and scampering. This one is the same, and the anthropomorphism (done well) is the hook here. On page 21 we get a description of Dragon, the cat: “He was enormous, with a huge, broad head and large mouth full of curving fangs, needle sharp.” Vivid, as a cat would be to a mouse, then the monstrous and mythical take over, “He had seven claws on each foot and a thick, furry tail, which lashed angrily from side to side.” Other thoughts—

• Honor and respect are heavy themes. In the first scene with the crow, throughout. The nature of true nobility. And a great quote from p. 32, “All doors are hard to unlock until you have the key.” 
• Little details like the smell of frost melting make the reading delightful. Twists and turns in plot too, like the drugged cat, the backstory, overhearing the family planning to poison the rats. There’s adventure and death/violence on a level that would not be possible for this age group with human characters.