The CBS Radio Mystery Theater was a radio drama series created by Himan Brown that was broadcast on CBS Radio affiliates from 1974 to 1982. Hot on the heels of the release of the movie "American Graffiti" and taking advantage of the 1950s nostalgia fad that swept through America in the 70's. Remember Happy Days, Laverne and Shirley and Grease? Because radio mystery drama was reminiscent of that era, the program quickly developed a fan base among young listeners in addition to its target audience. The program was pitched, at least initially, to an audience old enough to remember classic radio; Brown was a legend amongst radio drama enthusiasts for his work on Inner Sanctum Mysteries, The Adventures of Nero Wolfe and other shows dating back to the 1930s.
Episodes were introduced by a host (E. G. Marshall) who provided pithy wisdom and commentary throughout. Unlike the hosts of those earlier programs, Marshall is fully mortal, merely someone whose heightened insight and erudition plunge the listener into the world of the macabre (in a manner similar to that of "The Man in Black" on yet another old time radio program, (Suspense). Each episode of CBS Radio Mystery Theater opened and closed with the ominous sound of a creaking crypt door, accompanied by Marshall's disturbing utterance, "Come in. Welcome. I am E. G. Marshall." Marshall hosted the program from January 1974 until February 1982, when actress Tammy Grimes took over for the series' last season, maintaining the format.CBSRMT was broadcast each weeknight, with three or four episodes being new originals, and the remainder were reruns. There were 1,399 original episodes. The total number of broadcasts, including reruns, was 2,969. Each episode was allotted a full hour of airtime, but after commercials and news, episodes typically ran for about 45 minutes.
Sources: Wikipedia and CBSRMT.com
You can download the entire CBSRMT collection, all 1,399 episodes for free via Archive.org
14 shows from the CBS RADIO MYSTERY THEATER 1978:
12 shows from the CBS RADIO MYSTERY THEATER 1980: