Our guest is Karlos K. Hill, Associate Professor and Chair of the Clara Luper Department of African and African American Studies at the University of Oklahoma. He joins us to discuss his unsettling and comprehensive new book, "The 1921 Tulsa Race Massacre: A Photographic History." It's a vast gathering of photographs that were taken before, during, and after the massacre, mostly by white photographers. (Some of the images are being published here for the first time.) Comparing these photos to those taken elsewhere in the United States at various lynchings, Hill sets out to document how white civilians, in many cases assisted or condoned by local and state officials, perpetuated a systematic attack on Black Tulsans -- their lives as well as their property. Also on our show today, commentator Mark Darrah shares a surprising, separate-yet-related anecdote from the World War I era of Oklahoma history in his essay titled "Subversive Acts."