What do you think?
Rate this book
The Holocaust Codes: The Untold Story of Decrypting the Final Solution
The urgent, dramatic and untold story of how, for four years, British and Allied codebreakers decrypted secret SS and Gestapo messages detailing the mass killings of the Holocaust, and how the Germans in turn deployed cryptanalysis to try and conceal their persecution of Europe's Jews. The compelling and fast-paced story is told by two central and opposing characters, who never meet each other.
At Bletchley Park, there is the legendary but unsung British codebreaker Nigel De Grey, shy, determined, nicknamed 'the Dormouse' by his colleagues. In Poland SS Major Hermann Hoefle, a former taxi driver from Salzburg, and one of the Third Reich's ruthless bureaucrats of mass death, oversees the operations of five concentration camps, including Treblinka.
De Grey fought hard to make sure the vital intelligence from decrypted signals reached Allied leaders and was acted on. Hoefle, meanwhile, used complex coded messages to try to conceal the SS mass killings.
De Grey worked with his American counterparts, as well as codebreakers and intelligence agents from the Soviet Union, France, The Vatican, Switzerland and Poland. He had dangerous enemies closer to home, a cabal of senior British government and intelligence officials disbelieved or ignored repeated intelligence reports about the ongoing Holocaust.
It is the story of a battle between good and evil, between life and mass death, a war of electronic wits and cat-and-mouse. Seventy-five years on, as Russian leaders face war crimes charges in international courts, the words 'Never Again' seem even more pertinent than ever.
At Bletchley Park, there is the legendary but unsung British codebreaker Nigel De Grey, shy, determined, nicknamed 'the Dormouse' by his colleagues. In Poland SS Major Hermann Hoefle, a former taxi driver from Salzburg, and one of the Third Reich's ruthless bureaucrats of mass death, oversees the operations of five concentration camps, including Treblinka.
De Grey fought hard to make sure the vital intelligence from decrypted signals reached Allied leaders and was acted on. Hoefle, meanwhile, used complex coded messages to try to conceal the SS mass killings.
De Grey worked with his American counterparts, as well as codebreakers and intelligence agents from the Soviet Union, France, The Vatican, Switzerland and Poland. He had dangerous enemies closer to home, a cabal of senior British government and intelligence officials disbelieved or ignored repeated intelligence reports about the ongoing Holocaust.
It is the story of a battle between good and evil, between life and mass death, a war of electronic wits and cat-and-mouse. Seventy-five years on, as Russian leaders face war crimes charges in international courts, the words 'Never Again' seem even more pertinent than ever.
368 pages, Paperback
Published October 21, 2025
25 people are currently reading
260 people want to read
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 8 of 8 reviews
December 28, 2025
This book presents a compelling (and sobering) look at an often-overlooked aspect of World War II (or basically any war I‘d say): the role of intelligence, cryptography, and codebreaking in uncovering the realities of the atrocities that had happened, Holocaust in this case. It is presented how intercepted communications helped reveal the scale and intent of the Nazi regime’s 'Final Solution' - offering an important reminder of how information, and the failure to act on it, can (re)shape history🙂↔️
The moral weight carried by those who decoded these messages and those who chose to ignore or delay responding to them is also nicely portrayed; the historical implications are quite chilling, which makes this read a must for anyone interested in wartime intelligence/Holocaust history
With all that said - the execution felt uneven at times😅
While the research is clearly extensive, the narrative can be dense (and occasionally repetitive khm), which made certain sections feel more like an academic report than a cohesive historical account - and that‘s where I started slowly losing interest and the will to continue with reading
Don‘t get me wrong, I had finished reading it, but at moments I felt like completely giving up on it ehhh
I also wanted to read about a deeper exploration of the human impact behind the codes - the voices and experiences that could have added greater emotional resonance to the technical details; but oh well…
Overall, this is an informative and important book BUT it will definitely resonate more with readers who are already deeply invested in military intelligence or cryptographic history; from me a ✨solid✨ 3 stars for its subject matter and research - even if the storytelling itself doesn’t always fully engage (or hold your attention)
The moral weight carried by those who decoded these messages and those who chose to ignore or delay responding to them is also nicely portrayed; the historical implications are quite chilling, which makes this read a must for anyone interested in wartime intelligence/Holocaust history
With all that said - the execution felt uneven at times😅
While the research is clearly extensive, the narrative can be dense (and occasionally repetitive khm), which made certain sections feel more like an academic report than a cohesive historical account - and that‘s where I started slowly losing interest and the will to continue with reading
Don‘t get me wrong, I had finished reading it, but at moments I felt like completely giving up on it ehhh
I also wanted to read about a deeper exploration of the human impact behind the codes - the voices and experiences that could have added greater emotional resonance to the technical details; but oh well…
Overall, this is an informative and important book BUT it will definitely resonate more with readers who are already deeply invested in military intelligence or cryptographic history; from me a ✨solid✨ 3 stars for its subject matter and research - even if the storytelling itself doesn’t always fully engage (or hold your attention)
November 8, 2024
This recently published book (2024) is the result of mostly original research by Christian Jennings. His previous 10 books have all received good reviews on Good Reads.
It's his timeline story of the thousands German Police messages which were decrypted by the British code breakers almost in 'real time'
It is also a story of how and why these messages were covered up by the British. Only a very small group of individuals knew of their existence and this did not include the Head of Britain's Intelligence services.
These messages were mostly sent by the German Police who were at the forefront of the massacres in Poland, Russia, Italy and other occupied countries.
Center stage are two characters, Nigel de Grey in the UK and SS Major Herman Höfle in Germany.
This is a fairly easy to read book and is well written by Christian Jennings.
If, like myself, you know a little about this subject then by the end of the book you will have a good grounding through this excellent 'time line' presentation.
It's his timeline story of the thousands German Police messages which were decrypted by the British code breakers almost in 'real time'
It is also a story of how and why these messages were covered up by the British. Only a very small group of individuals knew of their existence and this did not include the Head of Britain's Intelligence services.
These messages were mostly sent by the German Police who were at the forefront of the massacres in Poland, Russia, Italy and other occupied countries.
Center stage are two characters, Nigel de Grey in the UK and SS Major Herman Höfle in Germany.
This is a fairly easy to read book and is well written by Christian Jennings.
If, like myself, you know a little about this subject then by the end of the book you will have a good grounding through this excellent 'time line' presentation.
February 13, 2025
I’m surprised about how much Bletchley Park decoded during the war. Now I know why. Also,when the decryption was too advanced in some cases, that’s where the Bombe comes in.
One of the consequences of being at war is keeping things secret. Without giving too much away, look at what happened when an indirect reference to what was happening to the Jews. That is why things had to be kept quiet.
But then at the end of the day, if there’s no traffic coming through from the camps, how can you back the decrypts up?
A fascinating read.
One of the consequences of being at war is keeping things secret. Without giving too much away, look at what happened when an indirect reference to what was happening to the Jews. That is why things had to be kept quiet.
But then at the end of the day, if there’s no traffic coming through from the camps, how can you back the decrypts up?
A fascinating read.
January 9, 2025
Insightful historical recap of the dynamics between British and German intelligence units in WWII. Enjoyed how the strategic aspect of using intelligence was developed throughout (one thing to have intelligence, a whole other to use it effectively without compromising sources).
December 31, 2025
Lots of quotes that involve repeating whole telegrams between German officials. Had me feeling like "this could have been an email" for awhile.
The world of Bletchley Park & Co is always a good starting point, but this didn't connect for me.
The world of Bletchley Park & Co is always a good starting point, but this didn't connect for me.
December 13, 2024
A very thoroughly researched and well written book regarding the horrors of the holocaust.
December 15, 2025
Very good narrator. With so much factual and statistical info, it was easier to listen and read. Difficult to hear about atrocities but glad to have done it. Probably wouldn’t recommend.
December 29, 2025
4.5⭐️ so many things I didn’t know about the holocaust it was a really interesting but sad read
Displaying 1 - 8 of 8 reviews