ON a stifling Saturday in Texas in June 1937 a twenty-six-year-old African-American musician, Robert Johnson, stepped to the microphone in a makeshift recording studio in a disused warehouse atop a Buick showroom. Johnson had grabbed a ride west from his native Mississippi to make it to the recording session in Dallas, one more journey in a life that had been spent by and large on the road. In contemporary parlance, he was a songster: an itinerant guitarist and maker of songs who scraped together a living wherever he found it, performing on street corners and in juke joints in the Deep South, sometimes drifting north, even reaching New York City, but always heading south again. That he recorded at all came down largely to luck; luck, and the exigencies of the Great Depression, which cut deeply into record company profits and forced the so-called ‘race record’ companies, which sold to an almost entirely black market, to look for cheap talent, Southern performers with local reputations who might appeal to regional markets. Johnson was one of many who caught a talent scout’s ear in the Mississippi Delta in the late 1930s. On that Saturday in Dallas he recorded fifteen songs, among them a haunted blues called ‘Hellhound on my Trail’.