The Man Called X
The Man Called X was a old-time radio espionage drama series that aired on and off from 1944 through 1951.
Herbert Marshall stars as Ken Thurston, a globe hopping government agent. The show opens with the familiar line "Wherever there is mystery, intrigue, romance, in all the strange and dangerous places of the world, there you will find The Man Called X".
Thurston works diligently every week to make the world a safer place by thwarting Cold War enemies and cooling off hotspots of unrest wherever they may be. He is aided/thwarted by his everpresent chiseling "sidekick" Pegon Zeldschmidt, played by Leon Belasco.
If you like this show, you will probably enjoy Dangerous Assignment.
Here is a sample of the online episodes currently available at The Old Time Radio Fan: