The Mercury Theatre on the Air web site is a project to make available as many of the original Mercury Theatre programs as possible. To quote the site: “The finest radio drama of the 1930’s was The Mercury Theatre on the Air, a show featuring the acclaimed New York drama company founded by Orson Welles and John Houseman. In its brief run, it featured an impressive array of talents, including Agnes Moorehead, Bernard Herrmann, and George Coulouris. The show is famous for its notorious War of the Worlds broadcast, but the other shows in the series are relatively unknown. This site has many of the surviving shows, and will eventually have all of them.
“The show first broadcast on CBS and CBC in July 1938. It ran without a sponsor until December of that year, when it was picked up by Campbell’s Soup and renamed The Campbell Playhouse. All of the surviving Mercury Theatre shows are available from this page in RealAudio format (some are also in MP3 format). There are several Campbell Playhouse episodes available here as well, in both RealAudio and MP3 formats; the rest are being added gradually.”
For genre audiophiles, a quick glance shows Dracula (originally broadcast 11 July 1938), Around the World in 80 Days (23 October 1938), The War of the Worlds(30 October 1938), and many more.