It was my privilege to have been a member-one of the "Wissende"-in this secret movement, which is legally known as the Knights of the Ku Klux Klan; and I had the opportunity of investigating it from the inside, observing its direful potentialities. When I became thorough acquainted with the thing, I withdrew from it, as I felt that it was dangerous, vicious and absolutely out of place in the American Republic. I therefore decided to expose it, and to make the "Invisible Empire" visible to the people of the United States. To accomplish this desired end, I turned over to the New York World all of the information I possessed; and that great newspaper, after three months of nation-wide investigation, told the people the truth about Ku Kluxism, and the "Invisible Empire." Supplementary to the work of the New York World, I offer this book, which consists largely of articles written as an investigator for that newspaper, many of which were used as a basis for its investigations.