Covert Radio Agents, 1939–1945: Signal From Behind Enemy Lines—David Hebditch (Barnsley, U.K.: Pen and Sword Military, 2021, 311 pp.)

The subject of covert radio agents operating behind enemy lines during World War II has recently taken on a life of its own. In the last five years, there have been no fewer than 16 books written on the subject. It is difficult to pinpoint the reason for the lingering popularity of this genre. Perhaps it is the mystery associated with spies, secrets, clandestine radios, and sabotage, which has been the grist of historical novels and movies for over 80 years. It may also be the fact that highly classified files and documents have been slowly released to the public over the years. Several of the recent authors cite in the prefaces of their books that they are using original information recently uncovered or unclassified.