Little is known of the first Behind the Mike, of 1931. The 1940 series was billed as "radio's own show, the stories behind your favorite programs, favorite personalities, and the radio people you never hear of." Guests included Lee De Forest, whose inventions of the audion and the "wireless telephone" made radio possible, and Walter Compton, who told of heartwarming listener response to the plight of an unfortunate on his Double or Nothing series. Graham McNamee told of announcer fluffs, revealed "what happens when a daytime serial needs firing up," described a "sound effect of the week," and read letters from listeners.