About The Book

In the midst of World War II, Enigma codebreaker Alan Turing has created a machine named Nautilus that can send a message back into the recent past. After Turing uses it to help the Allied forces succeed on D-Day, he sees the power (and potential danger) of what he has created. He knows he can only entrust it to one person: Joan, the mother of his secret child.
Over the next seventy years, the Nautilus is passed down through the Turing family, who all must decide for themselves when to use this powerful invention. Will it save the world - or destroy it?

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.

Series by the Author

Product Details

  • Publisher: Simon & Schuster Australia (June 30, 2026)
  • Length: 320 pages
  • ISBN13: 9781761639951

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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

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