Mrs. Frisby and the Rats of NIMH has been reprinted in paperback as The Secret of NIMH, partially because of the movie's title and because many prospective readers were put off by a book about rats. O'Brien himself stated that people often asked him why he chose to write about rats. He also noted that one of the first reviews of this book admitted that the title had put the critic off but once beyond that mental block the critic went on to write one of the most enthusiastic reviews. Rats, however, are only some of the novel's many believable and entertaining characters, which include humans, mice, owls, crows, and cats.

Mrs. Frisby and the Rats of NIMH tells two stories simultaneously: one is the struggle of Mrs. Frisby to find a way to save her home and to save her son Timothy from a life-threatening illness; the second is the story of the rats of NIMH, their escape to the Fitzgibbon farm, and their plan to move to Thorn Valley. The two stories are interwoven for Mrs. Frisby and the rats end up working together, for different purposes but for similar ends.

Although never spelled out in the novel, NIMH is the acronym of the National Institute of Mental Health, a government laboratory where some of these rats and mice were kept for three years before they escaped.

Mrs. Frisby and the Rats of NIMH examines issues of loyalty, independence, and courage, and debates the ultimate uses of knowledge and science....

(The entire section is 359 words.)