Discovering Mississippi's 'lost' blues music masters
12 September 2013 Last updated at 00:50 BST
In the summer of 1967 university student George Mitchell travelled to Mississippi in search of America's undiscovered blues musicians.
Many of the singers he heard were unknown beyond their home communities, and Mitchell's recordings helped make musicians such as RL Burnside and Fred McDowell blues music legends - and transform their lives.
Mitchell spoke to the BBC about his trip, chronicled and illustrated in his new book Mississippi Hill Country Blues 1967.
Produced by Sune Engel Rasmussen; edited by Bill McKenna
Picture This is a series of video features published every Thursday on the BBC News website which illustrate interviews with authors about their new books.