Proving Ground: The Untold Story of the ENIAC Programmers Who Pioneered Modern Computing

In the early 1940s, when the world was caught in the turmoil of World War II, six remarkable women were about to make history. Betty Holberton, Kay McNulty, Marlyn Wescoff, Ruth Lichterman, Betty Jean Jennings, and Fran Bilas stepped into a role no one had imagined—the world’s first professional computer programmers.

Their extraordinary story is meticulously detailed in Proving Ground: The Untold Story of the Six Women Who Programmed the World’s First Modern Computer, written by Kathy Kleiman. This powerful book shines a light on a hidden chapter of technological innovation and celebrates the brilliance, resilience, and quiet determination of six pioneers whose contributions were almost erased from history.

The Need for a New Kind of Machine

During the summer of 1942, the U.S. Army was grappling with a critical problem. Creating artillery firing tables, which were used to guide the trajectory of weapons, was a slow and error-prone process. Human “computers”—hundreds of women with degrees in mathematics—performed these calculations by hand. Each set of tables could take weeks to produce, and every calculation step carried the risk of introducing mistakes that could have life-or-death consequences in battle.

That was when John Mauchly and J. Presper Eckert proposed a bold solution: building an electronic machine capable of automating these calculations. Their idea would eventually become the ENIAC, short for Electronic Numerical Integrator and Computer. In many ways, ENIAC was the world’s first true electronic, programmable, general-purpose computer.

But there was a critical detail: no matter how powerful the machine was, it would be worthless without a program to tell it what to do. The software was as important as the hardware—something no one had fully grasped before.

The Selection of Six Trailblazing Women

At the time, programming did not even exist as a field. There were no programming languages, no manuals, and no training guides. The Army selected six women mathematicians from among their human computers to develop the code that would make ENIAC functional.

These women—Betty Holberton, Kay McNulty, Marlyn Wescoff, Ruth Lichterman, Betty Jean Jennings, and Fran Bilas—would become the first modern programmers. They were chosen not because anyone thought they were making history but because they were the only ones who truly understood the complexity of the calculations.

At first, the women were not allowed direct access to the ENIAC hardware. They had to rely on schematics, wiring diagrams, and logic charts to figure out how to make the machine perform complex operations. It was like learning to play a musical instrument without ever hearing it or touching it.

Inventing Programming From Scratch

The six programmers dove into the project with determination. With no precedents or examples to follow, they invented programming as we know it. They had to understand exactly how each of ENIAC’s units worked and how to configure cables and switches to create logic sequences.

This was not just a matter of translating math into machine instructions. It required a level of systems thinking and problem-solving that was unprecedented. They were effectively designing the first workflows of modern software engineering.

Their work culminated on February 14, 1946, when the ENIAC was publicly unveiled. During the demonstration, the computer performed calculations in about 20 seconds—tasks that had previously taken weeks. The event was a sensation, showing the world that electronic computing was not a fantasy but a revolution in progress.

Erased From the Narrative

Despite this monumental achievement, the six women were almost immediately written out of history. Newspaper articles covering ENIAC’s debut rarely mentioned their names. The credit was given to Herman H. Goldstine, the Army’s project officer, and to Adele Goldstine, who was compiling the first programming manual for ENIAC.

In photos published at the time, the women sometimes appeared, but captions did not identify them. When the author Kathy Kleiman, decades later, tried to learn more, she was told by the director of the Boston Computer Museum that the women were simply “models posing for publicity shots.”

This answer was unsatisfying—and completely false.

Kathy Kleiman’s Research Mission

Kathy Kleiman could not let the story end there. She embarked on years of research, interviews, and archival work, determined to uncover the truth. The result of her work is Proving Ground, a book that not only tells the story of these six women but also reclaims their rightful place in the history of computing.

Her work also inspired The ENIAC Programmers Project and a documentary series, Great Unsung Women of Computing, which have brought wider recognition to these trailblazers.

The Legacy of the ENIAC Programmers

The six women’s contributions were not limited to a single program. Over the years, they developed additional software that allowed ENIAC to solve differential equations, compute missile trajectories, and later even help with atomic research. Their work laid the foundation for countless innovations:

• Logical flow diagrams

• Subroutines and modular design

• Debugging methodologies

• Early documentation standards

Every modern software developer today is standing on the shoulders of these six women who invented the first programming frameworks in a time when the word “software” itself didn’t exist.

Why This Story Still Matters

Even today, women are underrepresented in computing and engineering. Knowing that the earliest programmers were women helps challenge stereotypes and inspire the next generation to see that technological innovation is for everyone.

Proving Ground is more than a historical account—it is a reminder that brilliance and determination can overcome any obstacle, including systemic bias and invisibility.

Where to Find the Book

Proving Ground is published by Grand Central Publishing. It spans 274 pages and is available in English, though as of this writing, no Spanish edition has been released. If you are interested in technology history, women’s contributions to STEM, or the origins of modern computing, this book is an essential read.

The story of the ENIAC programmers is a testament to the brilliance of six women who refused to accept the limits placed on them by society. They showed the world what was possible when intelligence, curiosity, and determination came together to create something entirely new.

Their legacy lives on in every computer, every software application, and every line of code written today.

Open Your Mind !!!

Source: ProvingGround (book)