Robert C. O’Brien's purpose in part tackles the issue of stereotypes in his novel Mrs. Frisby and the Rats of NIMH. The author attempts to break stereotypes with his descriptions of the small but feisty, Mrs. Frisby, and the rats who generally have a poor reputation. His purpose also tackles control over destiny and animal rights.
Mrs. Frisby is a tiny field mouse who defies the odds to save her young son who is sick with pneumonia. As spring arrives, she knows that she will have to move her family before the fields are plowed and their home is destroyed. Unfortunately, the son is so ill that she cannot move the family without help. She looks to a wise owl for support with her dilemma. Now in reality, an owl would just love a field mouse for a tasty treat but not in this book.
Ultimately, the “Rats of NIMH” come to her assistance. These are not usual rats who live on garbage and spread disease, these are rats who were educated to read and use electricity during their lives in NIMH. In this case, the rats are quite altruistic when dealing with Mrs. Frisby’s problems.