Department Z Books in Order

Two British amateur boxers offend a New York gangster after a newspaper misquotes them. They return to England, but Redhead follows with his men, bringing a threat that draws Department Z into action.

While visiting his aunt in the countryside, secret agent Jimmy Quinion receives orders to watch a farmhouse. An international conspiracy threatens millions of lives, and Department Z must stop the man behind it.

A poisoning at an exclusive London club draws Department Z toward a wealthy family. Gordon Craigie sends Hugh Devenish to investigate, but the search for a killer reveals a tangled web of theft and deception.

Leopold Gorman recruits five powerful men for a criminal scheme linked to the World Economic Conference. Refusal means death, leaving Department Z to confront a ruthless mastermind with ambitions far beyond London.

A crescent mark appears on orders for murder, sending Gordon Craigie and Department Z into a dangerous investigation. Starting at a country estate, they follow a trail involving drugs and an unidentified killer.

Two wealthy oil tycoons are murdered in their homes, raising fears for national security. Department Z agent Jim Burke investigates, only to become a target himself as he tries to prevent further killings.

Marius Krotz has become a dangerous influence behind the throne of a small European country. Department Z sends the Arran twins and Jim Burke against him before his plans can cause an international catastrophe.

A powerful man is stirring hostility between Britain and America as part of a wider plan for war. Gordon Craigie and Department Z must uncover his scheme before international tensions turn into mass killing.

Two Department Z agents run into trouble in the same English village. With a diamond-shaped card as his clue, Gordon Craigie must track three men planning a robbery that could cost many lives.

An ambassador is murdered in London, threatening to spark war with Britain. Gordon Craigie conceals the death while a Department Z agent races to find the killer before the diplomatic crisis becomes irreversible.

A visitor from Vallena warns Department Z agent Bob Kerr that both men are marked for death. As assassinations multiply, Kerr and his colleagues must dismantle a criminal organization threatening British officials.

A secret organization called the Ring has spread through several countries, provoking conflict and political violence. After an agent dies, Department Z must find a new way inside the network before its influence grows.

Cousins Mark and Mike Errol set out for a peaceful boat trip, only to stumble into a secret mission. Recruited by Department Z, they help confront a league holding Britain to ransom.

During London's wartime blackout, a silent assassin kills Department Z agents on watch. Gordon Craigie must discover how the murderer defeats trained operatives before the deadly method can be used by Britain's enemies.

German researchers on an island are developing gas that could paralyze soldiers, sailors and pilots. Department Z faces the dangerous task of stealing the formula and preventing the weapon from being used in war.

During the Blitz, destroyed food supplies and leaflets threatening starvation reveal an enemy operating inside Britain. Department Z investigates a campaign of sabotage, racing to identify an anonymous adversary before the damage becomes impossible to contain.

Department Z's Bill Loftus investigates blackmailers attempting to drive Britain and America apart. Powerful figures become entangled in the conspiracy, and a personal loss threatens his ability to stay focused while tracking the criminals behind it.

As Department Z works to stop British secrets reaching Berlin, three cousins meet privately in a Guildford cottage over a family matter. Their concerns intersect with an espionage investigation that leads toward a powerful spy ring.

A delirious French refugee washes ashore in England, repeating a strange phrase about Loftus. His arrival alerts Department Z to a Nazi scheme, forcing Bill Loftus and his colleagues to uncover a threat to British defenses.

Returning from America, David Garth receives an anonymous invitation and is recruited by Department Z agents pursuing a killer. A body in his burgled flat forces him into an investigation linked to America's support for the war.

Four important government officials are mysteriously blinded, and terrorists threaten the Prime Minister next. Gordon Craigie and Department Z must identify the weapon and find a cure before its creators use it to extend their power.

Professor Toller is kidnapped for a formula capable of producing a destructive weapon. Department Z chief Gordon Craigie investigates a seaside resort while international suspicions grow and a conspiracy threatens Britain's prime minister as well as its security.

Gordon Craigie and Department Z must protect an international conference in London. An attempt to assassinate a Russian diplomat threatens the negotiations, and the agents face an organized enemy capable of striking at the delegates.

Marlene von Barlack knows the private lives of powerful politicians through her intimate relationships with them. When one of her lovers threatens international peace, she must identify the conspirator as a manhunt spreads across the continent.

Charles Corliss appears an ideal recruit for Department Z, where his father once served. When missions start going wrong, the agents must confront the possibility that their charming new colleague has brought a dangerous enemy into their organisation.

Department Z sends Peter Ross to recover a kidnapped professor whose research could protect people from atomic attack. Power-hungry captors want the discovery for themselves, while Ross's feelings for two women complicate an already urgent mission.

Department Z faces an outside attack and a double agent within its ranks. As colleagues turn against one another, Gordon Craigie must identify the infiltrator before suspicion and counter-espionage destroy the British intelligence organization.

Journalist Nigel Murray rescues a kidnapped woman who is the niece of Canna's leader. Department Z draws him into investigating a conspiracy to overthrow the island's government, while his loyalty to her complicates the mission.