Cowboy Slim Rinehart was one of the first of the "Singing Cowboys", and a notorious one at that. He appears to have made his living from his music, and promoted it in the best ways he could. For the greater part, that was singing live over the radio.
Like JR Brinkley (Medical Quack), Rinehart was one of the earliest of the "Border Blaster" broadcasters. From the late 1930's until the '70's, a few adventurous broadcasters began sending their signals from just below the Mexican border. Because they were broadcasting using a Mexican license, they were under much less restrictions than were found on the legitimate American airwaves. The other benefit of broadcasting from Mexico was that the station's signal could be incredibly powerful. They were powerful enough that their signals could sometimes be heard near the Canadian border.
The power and freedom of the Border Blasters made them a favorite pitch device of some rather nefarious products, from hair-restorers to patent medicines to lonely-heart's clubs to "erection enhancers". Cowboy Slim Rinehart pitched various items, but his "money maker" seems to be his songbooks. When his friend Ernest Tubb signed with Decca Records, Tubb encouraged Rinehart to follow suit. The hesitation came because he was afraid that recording would cut into his songbook sales.
Rinehart appears to have been somewhat hardheaded on other issues. Apparently he became well enough noticed that Hollywood offered him roles in Singing Western movies during the early 40's, but he refused when he was told that he should adopt a stage name the was less "German sounding".
Fans of Cowboy Slim Rinehart agreed that he had the potential to make a large and lasting contribution to the growing Country Music scene. Tragically, he was cut down early by a car accident in Michigan. He was driving on his way to make his first commercial recording.