These race series recorded all sorts of interesting hot jazz, urban and rural blues, and gospel.

Not only were many of the songs hits within the blues market, but they also supplanted the standards that had been generated by more rural blues.

Meanwhile, the free showcases will look to older rural blues.

One of early rural blues, ragtime, and marching band music were combined with collective improvisation to create this new style of music.

The little-recorded Robert Johnson combined elements of urban and rural blues.

"Elvis introduced abstract thought into hillbilly music and rural blues," Mr. Thomas went on.

The balance of songs in World Gone Wrong swung more towards rural blues.

It's a wonderful collection thatdisplays the varieties of blues expression rather than suffering from an infatuation with rural blues.

A sense of fair play binds modern country melodies with rugged Southern gospel and the bottleneck guitar of rural blues.

"We like to offer a real cross-section of rural and urban blues," he said.