Although the collection is properly weighted in favor of rock 'n' roll's R&B forerunners, it does not neglect the rhythm-bound contributions made by country artists such as Hank Snow (represented here by his propulsive I am Movin' On), Hank Williams (Move It On Over), Merle Travis (Merle's Boogie Woogie), Tennessee Ernie Ford (the rollicking Shotgun Boogie), and the Delmore Brothers (Freigh