Based on their lineup alone, Brown's Ferry Four was a country supergroup from the get-go, with an original membership consisting of Grandpa Jones, the Delmore Brothers, and Merle Travis. Though the group only existed for ten years, and almost never made any personal appearances or gave any concerts, they managed to become one of the most beloved country gospel groups through their radio broadcasts and the nearly four dozen sides they recorded for King Records between 1946 and 1952. What makes them even more extraordinary for listeners in the 21st century -- even veteran country music hands -- is that their main virtue was their singing; the Delmores, of course, were well known for their harmonies, but neither Grandpa Jones nor Merle Travis was primarily known for his singing, except in the context of the Brown's Ferry Four. Complicating any account of their history, however, is the fact that thanks to the way they were put together legally, there were several versions of Brown's Ferry Four, and at least two could exist simultaneously; as they were almost exclusively a broadcasting and recording group, few listeners could keep track of the personnel changes. The group's origins go back to Cincinnati, Ohio in 1943, when a group called the Drifting Pioneers departed radio station WLW, leaving the station manager with a half-hour hole in his schedule that needed filling. Guitarist/singer Alton Delmore put together a quartet consisting of his guitarist/singer brother Rabon Delmore, banjo man/singer Grandpa Jones, and guitar virtuoso Merle Travis, all of whom had been playing in separate groups at the time. After a few dry runs and an agreement on some kind of repertory, they went on the air the next day, choosing the name from one of the Delmore Brothers' old songs at the...