Code Girls: The Untold Story of the American Women Code Breakers of World War II

This is a gray book cover with a gold title on the top, and a picture of five women smiling on the bottom. The women are dressed in old fashioned clothing.

Book written by Liza Mundy

Book review by Larry Pesce

Bottom Line

I recommend this nonfiction book for the Cybersecurity Canon Hall of Fame.

Executive Summary

Code Girls is the story of Dot Brayden, Carolyn Ruth, Wilma Berryman and a whole host of other women recruited into the Army Signal Intelligence Service at Arlington Hall. Compiled from interviews, research, and personal letters, Code Girls documents the struggles and accomplishments of the women codebreakers of WWII. The personal accounts of these women “Code Girls” illustrate both the technical and social challenges of women in the workforce in the 1940’s, but exemplifies the amazing mathematical and technical aptitudes and pure grit they displayed, ultimately making them as important (if not more so) than the soldiers on the front lines to the war effort, through the breaking of several Japanese cryptography systems.


Originally, I set out to listen to this book in audio format with my wife and two daughters as an inspiration for our family, that as a woman, anything is possible. As the subject of the book implies, this includes being an absolutely essential figure in a world changing event: becoming the driving force that broke many of the cryptographic methods employed during WWII. Certainly, my kids were inspired by all of the “Code Girls” that Mundy interviewed for this book for their tenacity and critical thinking! They both noted that we’ve grown a lot from the past and even have some more growing to do on securing a diverse workplace. 

From my perspective as a cyber security professional, hearing some of the technical details and hard work put in by the women in how they went about breaking the cryptographic functions was fascinating. After hearing how deduction, intuition, pattern recognition, the use of crib books of pre-discovered phrases, plaintext and key reuse, to inverse induction attacks, it really helped solidify some of the more modern equivalent concepts in my mind. The history behind how they performed these actions as both a mental exercise and with limited computing power made me realize that we’re still doing the same technical feats, just a heck of a lot faster!

The personal experiences of the women working in Arlington Hall made this book an incredibly enjoyable read, despite it being about some of the darkest times of the 20th century. I enjoyed learning about the living and work conditions, their personal tales, and how they came to be codebreakers; It was amazing to see folks from very diverse backgrounds come together to become such great friends and an unstoppable force.


Over the years I’ve become fond of Winston Churchill’s quote “Those that fail to learn from history are doomed to repeat it.”  Mundy’s recounting of the Code Girls activity, the struggles that they faced (socially, in the workplace, and breaking code) all hold some lessons from history. By learning from this history, hopefully we can improve for the future, both as a society, and implementers (and breakers) of cryptography. Due to these lessons, I feel that this is an important book and one worthy of the Cybersecurity Canon.

We modeled the Cybersecurity Canon after the Baseball Hall of Fame and the Rock & Roll Hall of Fame, except it’s a canon for cybersecurity books. We have more than 25 books on the initial candidate list, but we are soliciting help from the cybersecurity community to increase the number. Please write a review and nominate your favorite. 

The Cybersecurity Canon is a real thing for our community. We have designed it so that you can directly participate in the process. Please do so!