Themes 

Intelligence and ethics in science

Mrs. Frisby and the Rats of NIMH addresses intelligence through the rats' enhanced abilities, resulting from experiments at the National Institute of Mental Health. These experiments prompt ethical questions about altering nature. Led by Nicodemus, the rats deal with the impact of their intelligence and the moral duties it brings. They choose to form an independent community in Thorn Valley, reflecting a need to balance scientific progress with ethical values.

Community and civilization

Community and civilization are pivotal as the rats create a sophisticated society under a rosebush, complete with electricity and a library. Their effort to establish a self-reliant community goes beyond survival, representing a desire for moral and social advancement. Comparing their utopian society with their past dependent life raises questions about the essence of civilization. 

Survival

Survival drives the narrative. Mrs. Frisby's desire to protect her family parallels the rats' own survival challenges. Their joint effort to relocate Mrs. Frisby's home indicates survival relies on intelligence and ethical choices along with communal cooperation. The story argues true progress requires aligning intelligence and technology with courage and foresight.

Quick facts

• Mrs. Frisby and the Rats of NIMH won the Newbery Medal in 1972.

• Robert C. O’Brien was inspired by researcher John Calhoun’s experiments on mice and rats at the National Institute of Mental Health (NIMH) for the book.

• The rats in the story developed advanced intelligence and longevity due to experiments at NIMH.

• Mrs. Frisby and the Rats of NIMH addresses themes of sustainable living, societal evolution, and technological anxieties from the 1960s.

• The rats built an underground society with electricity, running water, literacy, and governance.

• Mrs. Frisby and the Rats of NIMH was ranked at 33 on the School Library Journal's list of the Top 100 Children's Novels.

• An animated film adaptation, The Secret of NIMH, was released in 1982.

• In the film, the character Mrs. Frisby was renamed Mrs. Brisby to avoid trademark issues with the Frisbee brand.

• The movie introduced a magical amulet representing Mrs. Brisby's inner strength, a feature not included in the original book.

• Robert C. O’Brien passed away two years after the book's publication; sequels expanding the original story, including Racso and the Rats of NIMH, were written by his daughter, Jane Leslie Conly.

• The audiobook version is performed by accomplished actress and award-winning narrator Barbara Caruso. 

Film adaptation

Mrs. Frisby and the Rats of NIMH inspired a 1982 animated film, The Secret of NIMH, directed by Don Bluth. While retaining the plot of a widowed mouse seeking help from intelligent rats, the film features significant changes from the book. The movie introduces magic with a new element. The lead character, renamed Mrs. Brisby for trademark reasons, receives an amulet symbolizing courage and power. This differs from the book's emphasis on inner strength and determination. Director Bluth explains that the amulet visually represents Mrs. Brisby's courage. The film also enhances Jenner's role as the primary antagonist, depicting him as a power-seeking rat to create dramatic tension. Additionally, the portrayal of Nicodemus as a mystical figure shifts from the book's scientific themes to a more fantastical focus.

About the author

Robert C. O'Brien, the pen name of Robert Leslie Carroll Conly, was an American author and journalist. He is best known for his children's novel, Mrs. Frisby and the Rats of NIMH, which won the Newbery Medal in 1972. Before writing fiction, he worked in journalism at National Geographic, Newsweek, and the Washington Times-Herald. He drew from research at the National Institute of Mental Health to write about scientific ethics and survival for both adults and young readers.