The Island of Peril — John Creasey

Department Z must stop the Nazis from deploying a deadly chemical weapon during World War II -- from the author who sold eighty million books worldwide.
 
On a top-secret island, the Germans are perfecting a paralyzing gas -- one that could disable an entire infantry troop, a crew of a ship, or the pilots of aircraft.
 
With the looming threat of this noxious gas, it's up to Department Z to find this mysterious island where the gas is being manufactured and steal the formula to prevent the Germans from using it as their ultimate weapon.
 
“Mr. Creasey realizes that it is the principal business of thrillers to thrill.” -- Church Times
 
“Little appears in the newspapers about the Secret Service, but that little makes anything on the subject probable fiction. Mr. Creasey proves himself worthy of the chance.” -- The Times Literary Supplement