Codebreakers
Thinking
One of the most common responses I get when talking about my work in a casual setting (dinner parties, weddings, airplanes) does something like “Oh, cool! I read a book on that once…”
They are almost always talking about Simon Singh’s 1999 The Code Book, which was also my own gateway to the subject in middle school. It’s obviously been a while since I read that one, but I recall it being a fun and informative read, where each chapter tackles a specific historic cipher. It even includes some puzzles in the back!1
But every now and then someone brings up David Kahn’s The Codebreakers—a much denser tome than Singh’s kid-friendly collection of anecdotes.
Kahn’s book, originally published in 1967 with a second edition in 1996, is still considered the best and most exhaustive history of cryptography, even though the first edition didn’t cover the most famous broken cipher in history: the Allied effort to break the Nazi Enigma codes. It sold over 75,000 hardcover copies in its initial edition, a monumental achievement for a book that was effectively a history textbook about mathematics and writing. The second edition included additional material covering the breaking of Enigma—which wasn’t public knowledge until the 1970s—and some other recent developments in cryptography, but the book hasn’t been updated or supplanted since.
Kahn died earlier this year. He remains a towering and well-respected figure among cryptology enthusiasts. The Codebreakers is certainly worth a read, if you have the time and energy to tackle a 1200-page book that spans several thousand years.2 Kahn, who later earned a doctorate in history at Oxford, built his career and writing style as a news journalist, which contributed to The Codebreakers’ continuing success.
But the book is not without its flaws. The price tag is one, though anyone who has ever bought a more academic history book wouldn’t be shocked by the price tag. It’s a great book to buy secondhand.
Its age is another flaw, through no fault of Kahn’s. Even much of the ancient history is out of date, having missed out on a half-century of scholarship. A large stretch of Arabic cryptography, in particular, has seen some groundbreaking work in the past fifteen years, accessible even to a nonspecialist like me who doesn’t read Arabic. Historical cryptography might be a niche field more popular with hobbyists than academics, but it is alive and well, though modern readers of The Codebreakers could easily remain in the dark about that fact.
The Codebreakers is also very much a product of its time. The second edition mostly just added content rather than undertaking any serious revision, and as such the book remains suffused with outdated language and a thoroughly Cold War-era American lens. The history told in the book is Eurocentric and reveals an underlying view of history that sees white Western culture as a culmination of centuries of incremental progress, with other cultures’ contributions considered mostly as stepping stones, anomalies, or exotic trivia. While this historiographical approach is certainly not unusual—and is alarmingly common even in modern popular histories—readers interested in the broad sweep of historical cryptography don’t have many other options.
I’m hoping to write up some further historiographical thoughts on this for a future post, about why I think Kahn was often asking the wrong questions about the history of cryptography. But for now, the book remains the only real comprehensive history on the topic, and I do truly think it was a crowning achievement of its time.
tl;dr: Read The Code Book if you want some fun reading or a book to give to a precocious kid in your life. Read The Codebreakers if you want a fairly readable 1200-word textbook, while keeping in mind it’s from the 1960s.
Reading
I’m in the middle of the audiobook for Brian Merchant’s Blood in the Machine, a history of the Luddite movement. I’m not quite as ignorant of the history as he assumes his reader to be (and most people might be, I don’t know!) but it’s been an interesting read so far. Merchant’s comparisons to Big Tech, as seen in the book’s subtitle, feel a bit forced and flatten two hundred years of history, but I can see why he went with that angle—and I’m curious to see where the second half of the book goes.
Doing
Turns out it’s hard to write when you have a newborn and two other kids. Who knew? (Everyone. Everyone knew.) Anyway, happy 2024! I’m hoping to get into a monthly cadence with these posts, even if only to try to shake some of the dust out of my brain.
IIRC there was a public cryptogram challenge when this book was initially published that has since been solved, but I’m sure there’s lots of info out there if you want to try your hand at it!
Some day I’ll write about the incredible hubris I had when I chose the same several thousand year span of cryptography to teach my very first class (on the quarter system, to boot!). We made it, but it was…a lot.