Classic radio mystery show that aired nationally between 1949-1962.
Featured the exploits of an insurance investigator who was frequently hired to investigate strange or mysterious insurance claims. These usually turned into full-blown murder mysteries. The show was built around the protagonist's expense account, and each scene was introduced by another line of that account ("$10.62 for a cheap suit that I bought as a disguise for the stakeout..."). At the end, Johnny summed up his expense report with the show's classic tag line, "Yours Truly, Johnny Dollar."
The show starred no fewer than eight actors over the years in the role of Johnny Dollar (Dick Powell, Gerald Mohr, Charles Russell, Edmond O'Brien, John Lund, Bob Bailey, Bob Readick and Mandel Kramer). Bailey was generally considered the best of the Dollars, playing the character with a hard-boiled, gritty realism.
You can still catch this show on many "old time radio" rebroadcasts, and it's available on tape and CD.
Insurance investigator! That's got to be the least glamorous lead character in any mystery show ever. Unless you count Quincy.