Raymond Chandler's famous private detective was brought to the airwaves in the late 1940's and early 1950's.
The character was first played by Van Heflin, but he was replaced by the much better cast Gerald Mohr. Mohr didn't have leading man looks, so his movie roles were usually small supporting parts, but on the radio he was the unquestioned lead. He had the perfect voice for radio and did a great job using it as his performances were always good. Very good.