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The Turing Protocol
Discover a past you never thought possible in this gripping, high-stakes historical thriller
Part of The Nautilus Series
By Nick Croydon
Table of Contents
About The Book
‘An incredible debut’ DON WINSLOW, New York Times bestselling author of The Cartel
‘The Time Machine meets The Da Vinci Code’ CHRIS HAMMER, internationally bestselling author of Scrublands
Humanity's best kept secret may be its best hope for survival.
In the midst of World War Two, Enigma codebreaker Alan Turing finds himself on the brink of a discovery that will change the world: a way to send a message back into the recent past. But when his invention successfully averts disaster on D-Day, the danger it poses in the wrong hands becomes terrifyingly clear. As Turing’s enemies close in, only one decision is possible: Nautilus must be kept hidden from the world, safe in the care of the only person he can trust.
Seventy-five years later, Annabelle McIntosh’s life is upended when she learns she will become the latest custodian of the greatest secret of the modern age – Turing’s Nautilus machine. Following in her family’s footsteps, and bound by Turing’s strict principles governing the use of his creation, Annabelle is soon faced with the same impossible choices. Nautilus has the power to prevent catastrophe, but the wrong decision could have devastating consequences.
When the stakes are at their highest, will using the machine save the world – or destroy it?
‘A smart, gripping thriller with an amazing big idea behind it. I loved it’ T.J. NEWMAN, internationally bestselling author of Falling
‘A fascinating alternative history with an intriguing “what if” at its core’ DERVLA McTIERNAN, internationally bestselling author of What Happened to Nina?
‘A ripping tale of past-careens-into-present fiction. Urgent morse code message to my past self: READ THE TURING PROTOCOL NOW’ TRENT DALTON, internationally bestselling author of Boy Swallows Universe
‘The Time Machine meets The Da Vinci Code’ CHRIS HAMMER, internationally bestselling author of Scrublands
Humanity's best kept secret may be its best hope for survival.
In the midst of World War Two, Enigma codebreaker Alan Turing finds himself on the brink of a discovery that will change the world: a way to send a message back into the recent past. But when his invention successfully averts disaster on D-Day, the danger it poses in the wrong hands becomes terrifyingly clear. As Turing’s enemies close in, only one decision is possible: Nautilus must be kept hidden from the world, safe in the care of the only person he can trust.
Seventy-five years later, Annabelle McIntosh’s life is upended when she learns she will become the latest custodian of the greatest secret of the modern age – Turing’s Nautilus machine. Following in her family’s footsteps, and bound by Turing’s strict principles governing the use of his creation, Annabelle is soon faced with the same impossible choices. Nautilus has the power to prevent catastrophe, but the wrong decision could have devastating consequences.
When the stakes are at their highest, will using the machine save the world – or destroy it?
‘A smart, gripping thriller with an amazing big idea behind it. I loved it’ T.J. NEWMAN, internationally bestselling author of Falling
‘A fascinating alternative history with an intriguing “what if” at its core’ DERVLA McTIERNAN, internationally bestselling author of What Happened to Nina?
‘A ripping tale of past-careens-into-present fiction. Urgent morse code message to my past self: READ THE TURING PROTOCOL NOW’ TRENT DALTON, internationally bestselling author of Boy Swallows Universe
About The Author
Photograph © Sarah Hellen Photography
Nick Croydon was born in Surrey, England, and is the CEO of QBD Books Australia. He has more than twenty-five years’ experience running international publishing companies and book retail businesses across the United Kingdom and Australia. The Turing Protocol is his debut novel. Nick is a father of four and husband to Esther, and he and his family spend their time between Brisbane, Spain and the UK.
Product Details
- Publisher: Simon & Schuster UK (August 28, 2025)
- Length: 400 pages
- ISBN13: 9781398552166
Raves and Reviews
‘I had a blast inside Croydon’s no-higher-stakes alt-20th-century playground. A wildly imaginative distortion of deeply researched historical fact forming a ripping tale of ‘past careens into present’ fiction. Urgent morse code message to my past self: READ THE TURING PROTOCOL NOW.’
– Trent Dalton
‘A remarkable debut novel from Nick Croydon. A smart, gripping thriller with an amazing big idea behind it. I loved it and I can’t wait for the movie and the sequel.’
– T.J. Newman
‘An incredible debut thriller where the past can be changed to save the future.’
– Don Winslow
‘A thought-provoking alternative history. The Time Machine meets The DaVinci Code.’
– Chris Hammer
‘Vivid, tense and sharp – Croydon’s concept will leave your mind and morals delightfully tangled.’
– Candice Fox
‘A fascinating alternative history with an intriguing ‘what if’ at its core. A great read.’
– Dervla McTiernan
‘The Turing Protocol is ideal for fans of The Imitation Game, The Time Traveler’s Wife, or The Man in the High Castle, and the film Oppenheimer. It’s a smart, emotionally resonant thriller that asks: what if the past could be rewritten – and what would we risk to do it? An ambitious and compelling debut. Highly recommended.’
– Megan Rogers
‘An intriguing mix of extraordinary fact and tense fiction’
– Sunday Telegraph
'Absorbing romp.'
– Good Reading
'The Turing Protocol is as thought-provoking as it is entertaining.'
– Meredith Jaffe
Resources and Downloads
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Book Cover Image (jpg): The Turing Protocol
eBook 9781398552166
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Author Photo (jpg): Nick Croydon Photograph © Sarah Hellen Photography(0.1 MB)
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