Donald William ` Bob ' Johnston ( May 14 , 1932 -- August 14 , 2015 ) was an American record producer , best known for his work with Bob Dylan , Johnny Cash , Leonard Cohen , and Simon and Garfunkel .
Donald William ` Bob ' Johnston ( May 14 , 1932 -- August 14 , 2015 ) was an American record producer . He was best known for his work with Bob Dylan , Johnny Cash , Leonard Cohen , and Simon and Garfunkel .