Inner Sanctum Mysteries was a highly popular old-time radio show that aired from 1941 to 1952. It featured stories of mystery, terror, and suspense, setting a standard for horror narrators with its tongue-in-cheek, dark humor, and unique tone. The show was created by producer Himan Brown and featured a spooky organ score by Lew White. Raymond Edward Johnson served as the show's original host, introducing himself as "Your Host, Raymond," and later replaced by Paul McGrath in 1945. Its iconic creaking door sound effect, which opened and closed each episode, gave the show an eerie atmosphere that resonated with listeners. Boris Karloff, Claude Rains, and Frank Sinatra were among the well-known guest stars in the early years of the program.

The series was highly successful, and although over 500 episodes were broadcast during its initial run, only around 200 episodes are available today. Inner Sanctum Mysteries is remembered for its chilling stories and memorable performances, leaving a lasting impact on the horror genre in radio and beyond.