Woody Guthrie is the most famous and influential folk music composer and performer in the history of the United States. His most popular song, "This Land is Your Land" has become the country's unofficial national anthem, known to every school child since the 1960s. His influence exceeded the realm of American music, reaching American politics. Guthrie's music became the soundtrack to the Great Depression, and iconic of the Dust Bowl migrants. Guthrie...