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Code Girls summary

Name: Code Girls
Rating: 4.6 (54 reviews)
Author: Liza Mundy

Liza Mundy

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

4.6 (54 ratings)

27 mins

9 key ideas

Audio & text

What is Code Girls about?

Code Girls (2017) is about the thousands of American women who worked as code breakers during World War II. Informed by interviews with over 20 surviving women, archived documents, and recently declassified oral histories, author Liza Mundy details the unprecedented lives of female code breakers in Washington, DC and beyond as well as the American intelligence that led to the success of the Allied war efforts.

About the Author

Liza Mundy is an award-willing journalist and author of the New York Times bestselling The Richer Sex: How the New Majority of Female Breadwinners Is Transforming Sex, Love and Family. She has contributed to publications such as TIME, the Guardian, the New Republic, and Slate and was previously a reporter at the Washington Post. As a senior fellow at the think tank New America, she is a leading expert on women and work issues.

Table of Contents

Code Girls
summarized in 9 key ideas

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Key idea 1 of 9

Cryptography bureaus often took on female workers because of the work’s grueling nature.

Cryptography, or code making, is as old as human communication itself. It dates back to some early point in time when a person first wanted to say something that not everyone was supposed to know.

Naturally, making codes is particularly useful in times of war. During the Civil War, for example, the Confederates devised a cryptographic system so complex that it confused even them.

In the early 1920s, however, American code breaking lagged behind that of countries such as France and England. In 1928, the US secretary of state even shut down military intelligence’s modest cipher bureau as it was bad manners to read other people’s mail.

But not everyone dismissed code breaking as immoral. And those who did see its purpose tended to favor women for the job. The assumption was that women were better able to focus intensely over long periods of time than men, who were seen as more intelligent but less patient. The assumption overlooked the fact that good code breaking requires both patience and intelligence.

In order to understand how code breaking works, let’s take a look at the two types of covert message systems: codes and ciphers. Codes are words, letters, or a string of numbers that represent words or phrases. Sometimes codes are used for brevity, in the same way that OMG is used today. But codes can also be used to disguise secret information from an enemy’s prying eyes; those meant to read the code could decipher it using a codebook.

Ciphers, on the other hand, are either a scrambling of letters known as transposition or a substitution of individual units with unique units – for example, substituting r for t. During the Renaissance, ciphers such as the Vigenère square were created by lining up various alphabets into a table that could be referenced. But with the development of radio and the telegraph, governments needed more security. So they created cipher machines as well as developing complicated ciphers using mathematical equations.

Tackling messages intercepted by cable, airmail, or teletype – that is, cryptanalysis, or code breaking – involved many tactics. In some cases, codes were cracked by stealing codebooks from the enemy. But more often, cryptanalysts cracked codes by studying the frequency and placement of specific words, using mathematical equations, and deducing meaning through educated guesses.

Pioneering female code breakers helped pave the way for the pre-WWII US cryptanalytic force.

In the summer of 1916, Indiana native Elizebeth Smith arrived at Riverbank Laboratories, in Illinois.

Riverbank was run by an eccentric millionaire called George Fabyan, who was hiring researchers to prove the theory that Sir Francis Bacon was the true author of William Shakespeare’s works. Bacon allegedly confessed his authorship in a cipher that was printed in Shakespeare’s First Folio. Needless to say, it didn’t take Elizebeth long to question the existence of the code she was enlisted to crack.

The army and navy competed to recruit female code breakers from elite colleges and small towns.

When Japan attacked Pearl Harbor on December 7, 1941, the United States was taken by complete surprise. The preemptive military strike and Japan’s subsequent declaration of war made it clear that the US military urgently needed to strengthen its intelligence.

As it turns out, the navy had been scouting recruits for its cryptanalyst office even before the attack. Agnes Meyer Driscoll may have been a great asset, but the office was still too small to handle the load of work that needed to be done. And in addition to recruiting men from leading colleges and universities, the navy wanted patriotic women with a liberal arts education and a demonstrated talent for foreign languages, science, and math. They also wanted the women to be attractive, so that they would marry and leave the navy sooner rather than later once the war was over.

The lives of the g-girls marked a societal shift for women.

The women who moved to Washington, DC to become code breakers were known by locals as government girls, or g-girls. Of course, those outside of their workplace assumed that the g-girls were helping with menial office work. In reality, their work was extremely intense, with seven-day shifts of up to twelve hours.

Yet for most of these women, life in the capital was also a time of unprecedented freedom.

A civilian army code breaker named Genevieve Grotjan played a key role in breaking Japan’s Purple machine.

You’ve probably heard of Alan Turing, the British mathematician who pioneered code-breaking methods at England’s Bletchley Park. But there were also American women who contributed major cryptanalytic breakthroughs during World War II.

One of the biggest advances in code breaking during the war was cracking the Japanese cipher machine known to the Allies as Purple. It was a job that Elizebeth Friedman’s husband William, working in the army’s Signal Intelligence Service, was determined for his team of civilian code breakers to accomplish.

Working together, g-girls in Arlington Hall helped sink numerous Japanese ships.

Throughout the war, the g-girls faced sexism from male superiors, colleagues, and others outside of their workplaces. But while hierarchical structures prevailed in the navy, work at Arlington Hall was comparably egalitarian. At Arlington Hall, even newcomer code girls could become leaders of important units.

One such newcomer was twenty-three-year-old Bronxville native Ann Caracristi – known to her coworkers as Annie – who joined in 1942. Annie had an English degree, but Arlington Hall supervisor Wilma Berryman – an early recruit hired by William Friedman – noticed that she also had a talent for engineering; she promoted Annie to be the leader of her research unit.

Code girls broke and wrote codes that supported the D-Day landing in Normandy.

The code girls’ work on Japanese ciphers was pivotal in the US’s ultimate victory. But their work reached beyond the Pacific.

In 1943, one group of WAVES members was sent to Dayton, Ohio to live on a campus called Sugar Camp. There, the women helped build over 100 “bombe” machines – a design originally perfected by the British at Bletchley Park. As they would later find out, these machines were made to decipher messages intercepted from the intricate German Enigma ciphering machine.

G-girls were privy to both the horrors and the victories of the war.

When it came to sinking Japanese ships, the code girls took pride in their work.

Still, reading the details about the horrors of war was psychologically taxing. News about American casualties, especially at the violent end of the war, troubled many. In some cases, women were even aware that their enlisted husbands, boyfriends, or brothers were in danger without being able to do anything about it.

After the war, secrecy and sexism left the code girls with mixed career options.

A few months after the war was over, the women at Arlington Hall were thanked for their service and relieved of their positions. Some time later, army operations officer Stephen Chamberlin publicly announced that code breakers were responsible for saving thousands of American lives and shortening the war. But he didn’t mention that more than 10,000 of these cryptanalysts were women.

In fact, during her research the author found that much of the official information about the code girls’ contributions to the war effort had been classified for over 70 years. She had to petition to have it declassified. Given this, it came as no surprise that the women had mixed experiences when it came to their careers in the postwar years.

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Best quote from Code Girls

It was not easy being a smart girl in the 1940s. People thought you were annoying.

—Liza Mundy

Who should read Code Girls

History buffs
Espionage enthusiasts interested in the history of cryptography
Students of science or gender studies

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Code Girls summary

What is Code Girls about?

About the Author

Code Girls
summarized in 9 key ideas

Cryptography bureaus often took on female workers because of the work’s grueling nature.

Pioneering female code breakers helped pave the way for the pre-WWII US cryptanalytic force.

The army and navy competed to recruit female code breakers from elite colleges and small towns.

The lives of the g-girls marked a societal shift for women.

A civilian army code breaker named Genevieve Grotjan played a key role in breaking Japan’s Purple machine.

Working together, g-girls in Arlington Hall helped sink numerous Japanese ships.

Code girls broke and wrote codes that supported the D-Day landing in Normandy.

G-girls were privy to both the horrors and the victories of the war.

After the war, secrecy and sexism left the code girls with mixed career options.

Key ideas in Code Girls

Cryptography bureaus often took on female workers because of the work’s grueling nature.

Pioneering female code breakers helped pave the way for the pre-WWII US cryptanalytic force.

The army and navy competed to recruit female code breakers from elite colleges and small towns.

The lives of the g-girls marked a societal shift for women.

A civilian army code breaker named Genevieve Grotjan played a key role in breaking Japan’s Purple machine.

Working together, g-girls in Arlington Hall helped sink numerous Japanese ships.

Code girls broke and wrote codes that supported the D-Day landing in Normandy.

G-girls were privy to both the horrors and the victories of the war.

After the war, secrecy and sexism left the code girls with mixed career options.

Best quote from Code Girls

Who should read Code Girls

Categories with Code Girls

Books like Code Girls

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Code Girls summary

What is Code Girls about?

About the Author

Code Girls summarized in 9 key ideas

Cryptography bureaus often took on female workers because of the work’s grueling nature.

Pioneering female code breakers helped pave the way for the pre-WWII US cryptanalytic force.

The army and navy competed to recruit female code breakers from elite colleges and small towns.

The lives of the g-girls marked a societal shift for women.

A civilian army code breaker named Genevieve Grotjan played a key role in breaking Japan’s Purple machine.

Working together, g-girls in Arlington Hall helped sink numerous Japanese ships.

Code girls broke and wrote codes that supported the D-Day landing in Normandy.

G-girls were privy to both the horrors and the victories of the war.

After the war, secrecy and sexism left the code girls with mixed career options.

Key ideas in Code Girls

Cryptography bureaus often took on female workers because of the work’s grueling nature.

Pioneering female code breakers helped pave the way for the pre-WWII US cryptanalytic force.

The army and navy competed to recruit female code breakers from elite colleges and small towns.

The lives of the g-girls marked a societal shift for women.

A civilian army code breaker named Genevieve Grotjan played a key role in breaking Japan’s Purple machine.

Working together, g-girls in Arlington Hall helped sink numerous Japanese ships.

Code girls broke and wrote codes that supported the D-Day landing in Normandy.

G-girls were privy to both the horrors and the victories of the war.

After the war, secrecy and sexism left the code girls with mixed career options.

Best quote from Code Girls

Who should read Code Girls

Categories with Code Girls

Books like Code Girls

Discover the Blinkist catalogue

Popular titles

Most popular categories

Trending Collections

Code Girls
summarized in 9 key ideas