Created by Jerry Siegel and Joe Shuster, the Man of Steel first appeared in Action Comics #1 in 1938. The following year, the newspaper comic strip began and four audition radio programs were prepared to sell Superman as a radio series. When Superman was first heard on radio less than two years after the comic book appearance, the character took on an added dimension with Bud Collyer in the title role.
The Adventures of Superman originally aired from 1940 to 1951. The serial came to radio as a syndicated show on New York City's WOR on February 12, 1940. On Mutual, it was broadcast from August 31, 1942, to February 4, 1949, as a 15-minute serial, running three or, usually, five times a week. From February 7 to June 24, 1949 it ran as a thrice-weekly half-hour show. The series shifted to ABC Saturday evenings on October 29, 1949, and then returned to afternoons, twice-a-week on June 5, 1950, continuing on ABC until March 1, 1951. In all, 2068 original episodes of The Adventures of Superman were aired on American radio.
During World War II and the post-war years, the show, sponsored by Kellogg's Pep, was a huge success, with many listeners following the quest for "truth and justice" in the daily radio broadcasts, the comic book stories and the newspaper comic strip. Airing in the late afternoon (variously at 5:15pm, 5:30pm and 5:45pm), the radio serial engaged its young after-school audience with its exciting and distinctive opening, which changed slightly as the series progressed. (Source: wikipedia.org)