There are certain singer-songwriters, brilliant ones, who live and work in towns across the United States. White guys, in their 50s and 60s, who've benefitted in countless ways from the advantages of their demographic classification, yet remain unsung heroes of music in the Woody Guthrie continuum. These are guys who never achieved the recognition of a Bob Dylan or Steve Earle. The larger pop world pays little attention to their work, but they create anyhow, because that's what they do. Guys like Nathan Bell, over in Chattanooga, Tenn., or Butch Hancock, out in West Texas.