A cynical act of mimicry by Sonny Boy Williamson II sparked a blues legend, the latest chapter of which has been tackled in song by Randy Newman.Nowadays it would be called “identity theft”, but when he took the name Sonny Boy Williamson in the early 40s – a moniker already held by a distinguished blues singer and harmonica player who had been born in Tennessee on 30 March 1914 – the man born Aleck Ford, in Glendora, Mississippi, knew exactly what he was doing. The cynical act of mimicry was designed to further his career, and, decades later, the...