This week's guest, journalist J. Mark Powell, says that history books tell you what happened during the Civil War, but his new book, "Witness to War," allows readers to experience it firsthand through its witnesses: Union and Confederate, battlefront and homefront, soldiers, civilians (men, women, and a few children). The book is based on Powell's private collection of 500 letters, and he reads a poignant one from a freed slave, living in Canada, to her former masters. Llewellyn King and Adam Clayton Powell III co-host.