Rasco and the Rats of NIMH by Jane Leslie Conly, 288 pages

‘Racso, a brash and boastful little rodent, is making his way to Thorn Valley, determined to learn how to read and write and become a hero. His bragging and lies get him off to a bad start, but a crisis gives him the opportunity to prove his mettle. A worthy successor [to Mrs. Frisby and the Rats of NIMH, a Newbery Medal winner by the author's father].