Hardcastle’s Secret Agent
by Graham Ison

Detective Inspector Walter Hardcastle is following in his father’s footsteps, but is his rapid rise about to be threatened by a spate of disturbing break-ins linked to the war effort?

August, 1939. As war looms, Detective Inspector Walter Hardcastle is following in the footsteps of his father, Ernest, and progressing through the ranks of the Metropolitan Police. Summoned to the office of Charles Marriot, Deputy Assistant Commissioner of CID at New Scotland Yard, Walter learns that he has been promoted to a senior role at V Division, and is plunged into a top secret case when burglaries occur at the homes of those working on a new type of war submarine.

Could a German spy be behind the break-ins? When one of the burglaries ends with a double murder, the stakes get higher for Walter. Can he track down an enemy agent on the streets of London while also resolving another disturbing case?


An entertaining historical procedural that perfectly captures both period ambience and the challenges of policing in the mid-twentieth century


Suspenseful … Ison, a 30-year veteran of the Metropolitan Police’s Special Branch unit, makes good use of his experience in crafting a plausible plot

Publishers Weekly

Another strong entry in a consistently fine series

Booklist on Hardcastle's Quandary

Entertaining ... Readers will hope Hardcastle has a long career

Publishers Weekly on Hardcastle's Quandary

Engaging, as always, and a good choice for fans of Charles Todd’s two series set in the WWI era, one starring Bess Crawford and the other, Ian Rutledge

Booklist on Hardcastle's Runaway

Cleverly plotted mystery, awash with appealing historical details. Another surefire winner

Booklist on Hardcastle's Quartet

Graham Ison

During Graham Ison’s thirty-year career in Scotland Yard’s Special Branch he was involved in several espionage cases. He also spent four years at 10 Downing Street as Protection Officer to two Prime Ministers. He is an honorary agent of the US Army Criminal Investigation Command.

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Hardcastle’s Secret Agent by Graham Ison is available in the following formats

Hardback97807278503481st June 2021147 X 225mm208$14.99
Hardback978072785034831st March 2021147 X 225mm208£20.99
Ebook97814483051621st May 2021N/A208$14.99
Ebook97814483051621st May 2021N/A208£12.99
Hardback - Large Print978144830606030th December 2021145 X 222mm288$36.95
Hardback - Large Print978144830606028th October 2021145 X 222mm288£22.99
Paperback978178029778127th January 2022140 X 216mm208$17.95
Paperback978178029778125th November 2021140 X 216mm208£12.99
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