The Man Called X was an espionage radio drama which aired on CBS and NBC from July 10, 1944 to May 20, 1952. Herbert Marshall had the lead role of agent Ken Thurston who took on dangerous cases in a variety of exotic locations. Gordon Jenkins Orchestra supplied the background music.

Leon Belasco played Mr. X's comedic sidekick, Pagan Zeldchmidt, who always turned up in remote parts of the world because he had a "cousin" there. Pagan would annoy and help Mr. X.