In one volume: three classic Department Z detective novels by the Edgar Award–winning writer who sold eighty million novels worldwide.

Department Z is the super-secret team of investigators that works within British intelligence—now, this special collection offers three action-packed pre–World War II tales of mystery. Included are:

First Came a Murder
Sir Basil Riordon is a mysterious, frightening, and immensely wealthy man. But is he also a killer? After a member of an exclusive London club is poisoned, the head of England's elite secret service, Gordon Craigie, has to navigate among some important and intimidating people to find out.

Death Round the Corner
Leopold Gorman studies the World Economic Conference with interest—and then picks five rich and powerful men to bring his plan to fruition. If any one of them shows reluctance to fall in with his scheme, he'll be dead within the hour. The only thing standing in the master criminal's way is Department Z . . .

The Mark of the Crescent
The mark of the crescent signs an order for murder. Gordon Craigie and Department Z are embroiled in a desperate investigation involving drugs, and must uncover who is behind the mysterious mark before the anonymous culprit claims another victim. The trail starts at the country estate of Greylands—but where will the mark of the crescent lead?