8 Things You May Not Know About Mrs. Frisby and the Rats of NIMH

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Alex Luppens-Dale


Alex Luppens-Dale won the “Enthusiastic Reader Award” all four years of high school. She is a graduate of Sarah Lawrence College and received her MFA in Creative Writing from The New School. Her favorite genres are memoir, witches, and anything with cults. She lives in New Jersey. You can keep up with Alex's latest work at her website.

The first time I read Mrs. Frisby and the Rats of NIMH, I was in the third grade. My copy called it The Secret of NIMH to tie it in with the movie, which had come out more than a decade beforehand. I remember being into the book enough that I used Ask Jeeves to find “NIMH” and was astounded that it was a real place. I concluded with all of the logic of a 10-year-old that that must mean that Nicodemus and his community were out there somewhere.

The next time I encountered the super-smart rats of NIMH, I was in fifth grade and we were reading the book together as a class assignment. I will never be able to think of the word “apt” without remembering the lengths to which my teacher went to explain to us why the cat, Dragon, had “an apt name.” Showing all of the signs of the anxious perfectionist I was, I didn’t want anyone to know that I’d read the book before. This went out the window when I made eerily accurate predictions about what would happen to Mrs. Frisby and her family next based on the sequel books I’d read the year before. No one had read the sequels. I was safe. 

The book celebrated its 50th anniversary in 2021 and is currently available in a really nice anniversary edition. While I still remember Mrs. Frisby, Justin, and Nicodemus after all these years, there are a lot of things I didn’t know or didn’t remember about the author of Mrs. Frisby and the book itself. Join me on this journey through tunnels strung with Christmas lights. 

Pen Names and Prior Publication

Robert C. O’Brien (real name Robert Leslie Carroll Conly) wrote under a pen name because National Geographic, where he was an assistant editor, disapproved of outside publication. In his career as a journalist, Conly also worked for Newsweek and the Washington Times-Herald.

Commutes are the Worst

O’Brien began writing children’s books after being diagnosed with glaucoma, which caused him to be unable to drive after dark and led to his family moving closer to his office — this freed up the time he’d previously spent commuting for fiction-writing and cements my deeply scientific belief that commutes are the natural enemy of the creative process. When Mrs. Frisby and the Rats of NIMH won the Newbery Medal, his editor accepted the award on his behalf, ostensibly for health reasons, but it helped keep his true identity secret as well.

Want More Rats? We Have More Rats!

Did you know that there were more books? Racso and the Rats of NIMH and R.T., Margaret and the Rats of NIMH were published by O’Brien’s daughter, Jane Leslie Conly in 1986 and 1990 respectively.

What’s in a Name?

Mrs. Frisby’s name was changed in the movie to avoid legal issues with Whamo-O, the copyright holder of the Frisbee trademark. Thus, Mrs. Frisby became Mrs. Brisby on film, which necessitated the re-recording of some lines in the film and the splicing of others to create the name “Brisby.”

So Many Mice

The film rights were offered to Disney but they had recently done The Rescuers, another movie that featured very intelligent mice that were based on a series of books by Margery Sharpe.

Rodent Utopias

Some of the experiments described in the book were based on John B. Calhoun’s research at NIMH. Calhoun studied rodent populations and how overpopulation led to social breakdown. His conclusions were pretty depressing.

Yet More Mice

There was a direct-to-video sequel to the movie called Timmy to the Rescue that has nothing to do with the other NIMH books written by O’Brien’s daughter. It was widely panned but featured actors such as Eric Idle, William H. Macy, and Dom DeLuise (reprising his role as Jeremy the crow). 

Further Reading

In total, O’Brien wrote four novels. Z for Zachariah was his final novel and was finished by his daughter and wife following his death. His other books were The Silver Crown and A Report from Group 17

Making this list reminded me of all of the things I loved about Mrs. Frisby and the Rats of NIMH and what remains with me as an adult. Though I may not have remembered the names of Mrs. Frisby’s children, the idea that there is more in the world than we humans can see has stuck with me forever.