Hazel Dickens may not have been a household name, but she left an indelible mark on bluegrass music. The singer, who appeared at every installment of San Francisco's Hardly Strictly Bluegrass Festival since its inception in 2001, died today at the age of 75.

The singer was notable for her pro-unioin and feminist themes, and she appeared in the 1976 Barbara Kopple documentary "Harlan Country U.S.A." about a 1973 coal miners' strike in Kentucky, and her song "Black Lung" is part of the film's soundtrack. In 2001 director Mimi Pickering made a film about Dicken's life called "Hazel Dickens: It's Hard to Tell the Singer from the Song."

Dicken's was born in Mercer, West Virginia, and one of her best-known songs was an homage to her birthplace, "West Virginia My Home." Listen to more examples of her music at Smithonian Folkways.