When Johnny Cash signed to Rick Rubin's record label in 1993, he was a country music legend who, like his fellow Highwaymen Willie, Waylon and Kris, remained a fondly regarded yet completely marginalized Nashville figure, unheard on the radio and unseen on the charts. Cash's odyssey from oldies act to folk hero pivots on his first American Recordings album, a document of almost unbearable solitude and directness. It is a singular record, an instance...