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Codebreaker: The Untold Story of Richard Hayes, the Dublin Librarian Who Helped Turn the Tide of World War II
When Richard Hayes, a gifted polymath and cryptographer, was drafted by Irish intelligence services to track the movements of a prolific Nazi spy, Hermann Görtz, it set in motion one of the most remarkable episodes in Irish history.
What followed was a high-stakes game of cat and mouse that would wind its way through the capital and its suburbs, reverberate through the corridors of power, test the sympathies of those in high society, and even expand to jeopardise the Allied war effort.
Codebreaker is a riveting and deeply researched account of an extraordinary period of history – when Dublin became a hotbed of Nazi intrigue and the fate of an independent Ireland settled on the shoulders of an unassuming employee of the National Library.
234 pages, Paperback
First published September 21, 2018
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121 people want to read
About the author
Marc Mc Menamin
2 books14 followersMarc Mc Menamin is an Irish author, historian, documentary maker and secondary school teacher from Ballyshannon, Donegal, Ireland, currently residing in Dublin.
He holds a Masters of Arts in History and a Postgraduate Diploma in Teaching from his Alma Mater, the National University of Ireland, Galway (NUI Galway).
He has produced several award winning radio documentaries, such as Richard Hayes, Nazi Codebreaker, and Peter Daly Good Cop/Bad Cop. Furthermore, Mc Menamin alsoworks as a Freelance Reporter for RTÉ Radio 1's The History Show.
Mc Menamin has worked as researcher on a number of documentaries most notably TV3’s Sinn Féin: Who are they? As well as stints on Midweek and Tonight with Vincent Browne, he also worked as an intern to Stephen Donnelly (T.D.) in Dáil Eireann.
In addition to Richard Hayes, Mc Menamin has also researched 1920's Donegal Politician Major James Myles.
He released his first book, Codebreaker, in 2018.
He holds a Masters of Arts in History and a Postgraduate Diploma in Teaching from his Alma Mater, the National University of Ireland, Galway (NUI Galway).
He has produced several award winning radio documentaries, such as Richard Hayes, Nazi Codebreaker, and Peter Daly Good Cop/Bad Cop. Furthermore, Mc Menamin alsoworks as a Freelance Reporter for RTÉ Radio 1's The History Show.
Mc Menamin has worked as researcher on a number of documentaries most notably TV3’s Sinn Féin: Who are they? As well as stints on Midweek and Tonight with Vincent Browne, he also worked as an intern to Stephen Donnelly (T.D.) in Dáil Eireann.
In addition to Richard Hayes, Mc Menamin has also researched 1920's Donegal Politician Major James Myles.
He released his first book, Codebreaker, in 2018.
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Displaying 1 - 19 of 19 reviews
January 21, 2021
There has been a prodigious amount of research for this book and for that I would give the author top marks. However, the author's narrative style lets him down badly. To my mind, this reads like a student essay, a long and exhausting list of names, bios, and dates does not make for interesting nor engaging reading. A pass grade at best from this historian. Did an editor work on this manuscript? A good one would have wielded the blue pen, introduced footnotes and annexes to encompass the extraneous matter and encouraged the author to at least flesh out the main characters in order to bring them alive in the mind of the reader. As it is now, the book would be a wonderful source for an author looking to craft a story based on the relationship between the IRA and the Nazis during WWII, a neglected space in the present bibliography.
February 21, 2019
The untold story of Irishman Dr Richard Hayes, one of WWII's greatest codebreakers makes for a very interesting read, especially if you have even a passing interest in the history of that period. As most stories and histories of that time are told from the viewpoint of either the Allied or Axis side, the fact that Dr Hayes was working for the government of a fledgling country desperately trying to retain its neutrality despite the pressure coming from the Allies gives the story a pretty unusual context. The stories of the various Nazi spies (both German and Irish) who arrived in Ireland during the war are also new to me and informative and entertaining in their own right. Overall I found this to be very enjoyable and educational.
One minor issue - As mentioned by some other reviewers, the chronology of events can be quite confusing at times, particularly at the start of the book.
One minor issue - As mentioned by some other reviewers, the chronology of events can be quite confusing at times, particularly at the start of the book.
June 16, 2019
McMenamin's Code Breaker provides a relatively broad account of Ireland’s relationship with Germany and Britain during World War II and its quest to remain neutral, focusing on the various spies Germany sent to Ireland and the work of G2. In particular, he spends some time detailing the work of Richard Hayes, the Director of the National Library, who was recruited on a part-time basis by G2 to crack German ciphers and help interrogate prisoners. Hayes was a polymath, skilled as both a linguist and a mathematician. His approach to cryptography was mathematical, but also social and technical, spending time talking to spies, riflling through their possessions for clues, and using forensics on burned paper. He made a number of contributions to cracking German ciphers including being the first to identify the use of microdots and solving agent in-field radio and legation ciphers, the latter of which were used in the Ardennes offensive. After the war his work was officially recognized in a secret meeting with Churchill and MI5, and he continued as director of the National Library until 1967 when he took up a position of librarian for the Chester Beatty Library.
While the book is nicely written and interesting, it’s timeline jumps around a bit, much of the material about German spies in Ireland has been told previously, and the new focus on Hayes is a little thin, in part due to the lack of source material. It would have also been nice to get more technical explanation of how the ciphers worked and were cracked, and the text linked to its sources. It would have also been preferable if the hyperbole could have been dropped. Hayes work was important, and his story worth telling, but he was not all that ‘stood between Ireland and Nazi Germany’ and ‘the fate of the country and the outcome of the war’ did not rest ‘on his shoulders’. His work was far from ‘crucial’ to the war (though it no doubt influenced Irish position and policy), and had marginal effect on turning the tide in the Allies favour (by late 1944 the tide had long turned). And some statements simply don’t stack up. Gortz was arrested in November 1941 and the idea he could have tipped the Germans to the double-cross system or the plans to land in Normandy as claimed make little sense. This hyperbole aside the book provides a readable overview of Ireland’s approach to Germany and its spies and the efforts of Richard Hayes and his G2 colleagues.
While the book is nicely written and interesting, it’s timeline jumps around a bit, much of the material about German spies in Ireland has been told previously, and the new focus on Hayes is a little thin, in part due to the lack of source material. It would have also been nice to get more technical explanation of how the ciphers worked and were cracked, and the text linked to its sources. It would have also been preferable if the hyperbole could have been dropped. Hayes work was important, and his story worth telling, but he was not all that ‘stood between Ireland and Nazi Germany’ and ‘the fate of the country and the outcome of the war’ did not rest ‘on his shoulders’. His work was far from ‘crucial’ to the war (though it no doubt influenced Irish position and policy), and had marginal effect on turning the tide in the Allies favour (by late 1944 the tide had long turned). And some statements simply don’t stack up. Gortz was arrested in November 1941 and the idea he could have tipped the Germans to the double-cross system or the plans to land in Normandy as claimed make little sense. This hyperbole aside the book provides a readable overview of Ireland’s approach to Germany and its spies and the efforts of Richard Hayes and his G2 colleagues.
April 20, 2019
Fascinating account of the work of Richard Hayes and G2 Irish Army Intelligence during World War II, as well as the numerous, and sometimes hilarious, attempts by the Abwehr and the Nazis at infiltrating Ireland using undercover spies. While the book is titled towards the story of Ireland's code breaker, it is much more than that and gives a wide overview of the activities of German spies in Ireland in collaboration with former and current republicans, Richard Hayes' and the Irish Authorities' attempts at detecting, capturing and interrogating them, and how this all affected the delicate balance of Irish neutrality during The Emergency.
December 29, 2018
Intriguing account of Ireland's involvement in world war II - an area about which I had been get unaware.
Well researched and written book although I did find the narrative slightly hard to follow at times as it tended to jump from subject to subject a bit.
Definitely recommend for anyone interested in world war II history.
Well researched and written book although I did find the narrative slightly hard to follow at times as it tended to jump from subject to subject a bit.
Definitely recommend for anyone interested in world war II history.
November 21, 2018
This is a really entertaining book about a fascinating period of history. All sorts of great stories about German spies in Ireland.
Two small criticisms. The ordering of the events was a bit confusing. Figures showing how the cyphers worked like in Singh's The code Book would be of benefit.
Two small criticisms. The ordering of the events was a bit confusing. Figures showing how the cyphers worked like in Singh's The code Book would be of benefit.
April 18, 2022
An informative and detailed investigation of the effective work of a small group of code breakers to frustrate the activities of German spies in Ireland during WWII. An engaging insight into a little known aspect of Irish history.
June 29, 2019
This is an odd book.
It's well written, engaging, and comprehensive look at German espionage efforts in Ireland during the emergency. As such I would suggest that it would better be entitled to the more broad offering that it is.
It is not a biography of Dr Richard Hayes despite the title and if that's why you picked up you will be disappointed. Not disappointed in the book, but simply in how absent Hayes is from this narrative. He is mentioned and clearly, the results of his deciphering/codebreaking are an aspect of this book, but they are quite subordinate to the overall treatment.
McMenamin has delivered a superb first work, and comprehensive survey of the principal actors in German espionage efforts - both axis, allies and neutrals. He does a superb job of defining the very fine line that was pursued by the 'neutral'; Irish state during WWII as well as the strange politics that pitted IRA activists on the side of their enemies enemy - Germany.
The story is told largely in a chronological fashion, with some deviations to allow for the fuller story arcs of individuals. There's limited use of pictures and maps which would indeed have enlivened the relating of the tales. More importantly and I am being critical in this, it is a story of codebreaking and potentially of the codebreaker.
The codebreaker is identified and lightly covered. He (Hayes) pops into the more colourful tales of specific operatives but remains a very two-dimensional character. It is only when the book is being concluded that his life following 1945 is related. His pre-wartime and wartime lives are largely left undivulged. I am left with a sense that he is a unique person and well worth a biographical exploration and in that one may feel deprived.
Moreover, given the attention to breaking of codes, it would greatly benefit the less mathematically inclined to use graphic illustration or examples of the means by which encoded messages were turned from gibberish to value. In this, I clearly recall reading the biography of Leo Marks 'Between Silk and Cyanide' or even more well covered and explained in Codebreakers by David Kahn, where the authors do a notable job of explaining the techniques and methods of the codebreaker and of the particular means of encoding a text. In this volume, the author seems to presume a pre-existing knowledge of the same and refers to the technique and presumes the reader will either be aware or go off and do their own homework.
Nonetheless, I don't mean to come of hugely critical of unrealised potential or promises unfulfilled, although it is clearly a case of the latter. I would highly recommend this read to appreciate the perception that the various German espionage services held of the neutral state of Ireland and of the attempts to exploit this neutrality during the Second World War. In this, the author writes a compelling work and demonstrates superior scholarship. If only I hadn't been led to expect something entirely different by the title. The 'untold story' remains largely untold.
It's well written, engaging, and comprehensive look at German espionage efforts in Ireland during the emergency. As such I would suggest that it would better be entitled to the more broad offering that it is.
It is not a biography of Dr Richard Hayes despite the title and if that's why you picked up you will be disappointed. Not disappointed in the book, but simply in how absent Hayes is from this narrative. He is mentioned and clearly, the results of his deciphering/codebreaking are an aspect of this book, but they are quite subordinate to the overall treatment.
McMenamin has delivered a superb first work, and comprehensive survey of the principal actors in German espionage efforts - both axis, allies and neutrals. He does a superb job of defining the very fine line that was pursued by the 'neutral'; Irish state during WWII as well as the strange politics that pitted IRA activists on the side of their enemies enemy - Germany.
The story is told largely in a chronological fashion, with some deviations to allow for the fuller story arcs of individuals. There's limited use of pictures and maps which would indeed have enlivened the relating of the tales. More importantly and I am being critical in this, it is a story of codebreaking and potentially of the codebreaker.
The codebreaker is identified and lightly covered. He (Hayes) pops into the more colourful tales of specific operatives but remains a very two-dimensional character. It is only when the book is being concluded that his life following 1945 is related. His pre-wartime and wartime lives are largely left undivulged. I am left with a sense that he is a unique person and well worth a biographical exploration and in that one may feel deprived.
Moreover, given the attention to breaking of codes, it would greatly benefit the less mathematically inclined to use graphic illustration or examples of the means by which encoded messages were turned from gibberish to value. In this, I clearly recall reading the biography of Leo Marks 'Between Silk and Cyanide' or even more well covered and explained in Codebreakers by David Kahn, where the authors do a notable job of explaining the techniques and methods of the codebreaker and of the particular means of encoding a text. In this volume, the author seems to presume a pre-existing knowledge of the same and refers to the technique and presumes the reader will either be aware or go off and do their own homework.
Nonetheless, I don't mean to come of hugely critical of unrealised potential or promises unfulfilled, although it is clearly a case of the latter. I would highly recommend this read to appreciate the perception that the various German espionage services held of the neutral state of Ireland and of the attempts to exploit this neutrality during the Second World War. In this, the author writes a compelling work and demonstrates superior scholarship. If only I hadn't been led to expect something entirely different by the title. The 'untold story' remains largely untold.
April 7, 2022
The book was not what I expected – from the title/subtitle I was expecting a biography/delve into the work of Dr Richard Hayes & instead I got quite a comprehensive look into Ireland’s position during the war, and how things could have been very different. The book focussed far more on Hermann Görtz (Nazi spy) than on Richard Hayes (cryptographer) who is really quite absent from the main story.
At this time, Ireland was in a period of change, having established the Irish Free State in 1922 yet still being legally part of the UK. Though many Irish citizens, who were legally still British nationals, fought in the British Army, Ireland as a nation was determined to remain neutral. The leaders of the Irish government, particularly Eamon de Valera, were very aware of a risk of invasion from either Germany (who might want it as a strategic location for an invasion of the UK) or from the UK (who could try to re-establish their sovereignty if they felt the balance had tipped too far). We get interesting insights into the politics of the time, including the interesting question: if the IRA were enemies of the British, were they therefore allies of the Nazis? Some German forces certainly believed that forging links with the IRA could be beneficial to them!
The book focusses primarily on the work of various German spies that were sent to Ireland and the work of the G2 Irish Intelligence Service. Richard Hayes, the Director of the National Library, who was recruited on a part-time basis by G2 to help with cryptography, made some significant breakthroughs identifying the use of microdots, and cracking various ciphers.
The book is well researched, though many papers relating to Hayes & his codebreaking have been destroyed. However there are a lot of facts & figures, names & places to get your head round and at times it felt more like an essay or academic research paper than a book written for the general public to access. Readers will need to be somewhat familiar with some Irish terms such as Taoiseach (prime Minister/leader of the government).
Overall, this was an interesting book that gave a good insight into the tensions and politics in Ireland during WW2 – but I was expecting the book to be much more about the codebreaking and the man behind it than on the way that Nazi spies operated in Ireland during WW2! It wasn’t what the title implied it would be and I do think that it needs a rebrand/retitle in order to appeal to the audience that it is intended for.
I listened to the audiobook, read by Aidan Kelly, and I am pleased that an Irish narrator was used, it wouldn’t have worked with any other accent!
At this time, Ireland was in a period of change, having established the Irish Free State in 1922 yet still being legally part of the UK. Though many Irish citizens, who were legally still British nationals, fought in the British Army, Ireland as a nation was determined to remain neutral. The leaders of the Irish government, particularly Eamon de Valera, were very aware of a risk of invasion from either Germany (who might want it as a strategic location for an invasion of the UK) or from the UK (who could try to re-establish their sovereignty if they felt the balance had tipped too far). We get interesting insights into the politics of the time, including the interesting question: if the IRA were enemies of the British, were they therefore allies of the Nazis? Some German forces certainly believed that forging links with the IRA could be beneficial to them!
The book focusses primarily on the work of various German spies that were sent to Ireland and the work of the G2 Irish Intelligence Service. Richard Hayes, the Director of the National Library, who was recruited on a part-time basis by G2 to help with cryptography, made some significant breakthroughs identifying the use of microdots, and cracking various ciphers.
The book is well researched, though many papers relating to Hayes & his codebreaking have been destroyed. However there are a lot of facts & figures, names & places to get your head round and at times it felt more like an essay or academic research paper than a book written for the general public to access. Readers will need to be somewhat familiar with some Irish terms such as Taoiseach (prime Minister/leader of the government).
Overall, this was an interesting book that gave a good insight into the tensions and politics in Ireland during WW2 – but I was expecting the book to be much more about the codebreaking and the man behind it than on the way that Nazi spies operated in Ireland during WW2! It wasn’t what the title implied it would be and I do think that it needs a rebrand/retitle in order to appeal to the audience that it is intended for.
I listened to the audiobook, read by Aidan Kelly, and I am pleased that an Irish narrator was used, it wouldn’t have worked with any other accent!
March 23, 2022
Ireland had a difficult course to chart during WWII. The country decided to remain neutral, but was always aware of the risk of an Allied invasion if Germany began using the country as a staging point for operations against the UK. This book is mostly about the German attempts to do just that – to insert agents into Ireland that would provide intelligence useful against the British. Or, in some cases, to forge links with the IRA that could bring an armed force that could be used against them.
The author often reiterates the magnitude of the risk that this posed to the Allies, to some extent overusing the word “huge.” Set against the threat, the efforts of the German agents seem somewhat comically inept, especially against the brilliance of the title character, Dr. Richard Hayes. Hayes not only broke the German codes but also had a great deal of success in interrogating the captured German agents. However, the figure at the center of the story is Eamon de Valera, who had the task of negotiating between the much larger forces to maintain Irish independence.
The research is extremely impressive and the author convincingly presents Hayes as a hero whose effort’s during the war should be as well known as those of Alan Turing.
The author often reiterates the magnitude of the risk that this posed to the Allies, to some extent overusing the word “huge.” Set against the threat, the efforts of the German agents seem somewhat comically inept, especially against the brilliance of the title character, Dr. Richard Hayes. Hayes not only broke the German codes but also had a great deal of success in interrogating the captured German agents. However, the figure at the center of the story is Eamon de Valera, who had the task of negotiating between the much larger forces to maintain Irish independence.
The research is extremely impressive and the author convincingly presents Hayes as a hero whose effort’s during the war should be as well known as those of Alan Turing.
January 18, 2024
Poorly written and formulaic. The greatest irony of this book is that the person in which it is supposed to be about and the very subject itself, is hardly mentioned at all. Instead it should be regarded as a poorly written, terribly structured, biography of an appallingly bad spy. Even its notes on history are wrong, confusing the date of the storming of the Reichstag with that of Hitler’s death, or even stating hard fought battles to capture Paris when a paragraph later stating the city was taken without a fight. The author should be allowed no merits for regurgitation of documents in a basic form, and certainly derided for a “history book” without referencing or index.
August 15, 2019
This isn’t an easy read and is not very well written. However it is very informative and I have learnt a lot about how Ireland helped Allies to win the war. I have also learnt about Nazi sympathisers in Ireland and that Ireland refused Jewish refugees. De Valera played a strange game in preserving Ireland’s ‘neutrality’. The destruction of some many papers relating to Richard Hayes’s codebreaking must have made writing the book difficult and the writer is to be commended for putting the story together
December 14, 2025
I was hoping for a deep dive into Richard Hayes, his code breaking, and how he did it. Unfortunately this book isn't really "Codebreaker: the untold story of Richard Hayes" as much as it is "the story of Ireland during the war in which Richard Hayes plays a small but important part". Skip this book if you're interested in code breaking, give it a shot if you're interested in the war and Ireland's part in it.
May 12, 2021
Very interesting book. It illustrates the extreme tension that was present in Ireland during the war. I didn't know that England was on the brink of invading on more than one occasion. Some real surprises about the folks who settled in Ireland afterwards...
July 9, 2021
Very interesting account of an unsung hero in a very challenging time in our history. A fledgling State, trying to maintain a neutral position and being used and pressurised by both sides...
September 29, 2021
Not great
April 5, 2022
Fascinating
December 19, 2019
16 Jan 2019
October 30, 2022
Forgot to say I finished this :O
Displaying 1 - 19 of 19 reviews