In 1975, a black woman named Joan Little escaped the cell where she'd been sexually assaulted by a white jailer. Little was on the run when Sweet Honey in the Rock founder Bernice Johnson Reagon heard the news. Inflamed by this inequity, Reagon wrote the song Joan Little for Sweet Honey to perform.

Through the song, the politically-charged, all-female a cappella singing group helped raise awareness for the plight of the North Carolina woman, who was eventually acquitted for acting in self-defense. The song was the first Sweet Honey tune to hit the airwaves and, ironically, it wasn't played by a DJ, but by a news department. Says Reagon: "It should have been the indication that we were not going to break into the top 40."

Today, the sextet of African-American women continues to raise powerful voices against injustice with music born of spirituals, slavery and the Civil Rights Movement. "Sweet Honey is unique. It's the color of that voice, the passion," says music historian Horace Clarence Boyer in the AMERICAN MASTERS film Sweet Honey in the Rock: Raise Your Voice. "And then you pick up those words and you say 'my, my, this is something I need to pay attention to.' "