Terry Gross In 2013, historian Rhae Lynn Barnes was researching blackface in America when she encountered a stumbling block at the Library of Congress: Various primary sources on the subject were listed as "missing on shelf." Barnes spoke to one of the librarians, and explained that she was writing a history of minstrel shows and white supremacy. Barnes says the librarian admitted that, in 1987, she had personally hidden some of these books because she feared the material would be used by the Ku Klux Klan. "Once [the librarian] understood the research I was doing ... a few hours later, she came up with a cart packed to the brim with all of the material that I had been hoping to see," Barnes says. In her new book Darkology: Blackface and the American Way of Entertainment, Barnes traces the origin of minstrel shows, performances in which an actor portrays an exaggerated and racist depiction of Black, often formerly enslaved, people.…