Michael Shayne followed the adventures of a hard-boiled private detective, Mike Shayne, created by American crime novelist Brett Halliday. This gumshoe character was a reckless, red-headed Irishman who fought crime with a license and an attitude, adopting a loner persona akin to those of Mike Hammer and Phillip Marlowe. The show explored the darker streets of the American dream, focusing on adult themes like drugs and middle-class adultery. Mike was a believable and popular private eye, especially among post-WWII veterans who had experienced their fair share of violent morality. The radio version of the show started with Wally Maher in the title role, and its popularity led to continuous adaptations and revisions.

The radio show was broadcast from 1944 to 1953, during which time it aired on various networks and with different actors portraying Mike Shayne. The first radio version, Michael Shayne, Private Detective, debuted on the Don Lee Network in 1944, exclusive to the western United States. In 1946, the show was aired nationally on the Mutual network, followed by another national run in 1948 with a new title, The New Adventures of Michael Shayne, this time starring movie star Jeff Chandler. The show had another run in 1952-53, again titled as Mike Shayne, Private Detective, featuring Donald Curtis and Robert Sterling in the title role. The radio show was based on Halliday's novels featuring the character Mike Shayne, with almost three dozen episodes available for listening. In the early 1960s, a TV adaptation of Michael Shayne was produced with Richard Denning playing the lead role.

Sources: wikipedia.org, otrcat.com