Why did mrs Frisby and the Rats of NIMH wins writing awards?

Mrs. Frisby and the Rats of NIMH was a Newberry Honor Book and a New York herald Tribune Spring Book Festival award recipient for its writing. The novel is praised for its complex and well developed characters, its rich and imaginative world building and its thoughtful exploration of themes such as courage, friendship and family. Additionally, the novel is noted for its suspenseful and exciting plot that kept readers engaged from beginning to end.